SIMPLE SOLUTIONS

LIBCW(3) - Linux man page online | Library functions

General purpose Morse code functions library.

Chapter
CW Tutor Package
LIBCW(3) Library Functions Manual LIBCW(3)

NAME

libcw - general purpose Morse code functions library

SYNOPSIS

#include <libcw.h> int cw_generator_new(int audio_system, const char *device) void cw_generator_delete(void) int cw_generator_start(void) void cw_generator_stop(void) int cw_set_send_speed(int new_value) int cw_set_frequency(int new_value) int cw_set_volume(int new_value) int cw_set_gap(int new_value) int cw_set_weighting(int new_value) int cw_get_send_speed(void) int cw_get_frequency(void) int cw_get_volume(void) int cw_get_gap(void) int cw_get_weighting(void) void cw_get_send_parameters(int *dot_usecs, int *dash_usecs, int *end_of_element_usecs, int *end_of_character_usecs, int *end_of_word_usecs, int *additional_usecs, int *adjustment_usecs) int cw_send_dot(void) int cw_send_dash(void) int cw_send_character_space(void) int cw_send_word_space(void) int cw_send_representation(const char *representation) int cw_send_representation_partial(const char *representation) int cw_send_character(char c) int cw_send_character_partial(char c) int cw_send_string(const char *string) void cw_reset_send_receive_parameters(void) const char *cw_get_console_device(void) const char *cw_get_soundcard_device(void) const char *cw_generator_get_audio_system_label(void) int cw_register_tone_queue_low_callback(void (*callback_func)(void*), void *callback_arg, int level) bool cw_is_tone_busy(void) int cw_wait_for_tone(void) int cw_wait_for_tone_queue(void) int cw_wait_for_tone_queue_critical(int level) bool cw_is_tone_queue_full(void) int cw_get_tone_queue_capacity(void) int cw_get_tone_queue_length(void) void cw_flush_tone_queue(void) void cw_reset_tone_queue(void) int cw_queue_tone(int usecs, int frequency) int cw_set_receive_speed(int new_value) int cw_get_receive_speed(void) int cw_set_tolerance(int new_value) int cw_get_tolerance(void) void cw_get_receive_parameters(int *dot_usecs, int *dash_usecs, int *dot_min_usecs, int *dot_max_usecs, int *dash_min_usecs, int *dash_max_usecs, int *end_of_element_min_usecs, int *end_of_element_max_usecs, int *end_of_element_ideal_usecs, int *end_of_character_min_usecs, int *end_of_character_max_usecs, int *end_of_character_ideal_usecs, int *adaptive_threshold) int cw_set_noise_spike_threshold(int new_value) int cw_get_noise_spike_threshold(void) void cw_get_receive_statistics(double *dot_sd, double *dash_sd, double *element_end_sd, double *character_end_sd) void cw_reset_receive_statistics(void) void cw_enable_adaptive_receive(void) void cw_disable_adaptive_receive(void) bool cw_get_adaptive_receive_state(void) int cw_start_receive_tone(const struct timeval *timestamp) int cw_end_receive_tone(const struct timeval *timestamp) int cw_receive_buffer_dot(const struct timeval *timestamp) int cw_receive_buffer_dash(const struct timeval *timestamp) int cw_receive_representation(const struct timeval *timestamp, /* out */ char *representation, /* out */ bool *is_end_of_word, /* out */ bool *is_error) int cw_receive_character(const struct timeval *timestamp, /* out */ char *c, /* out */ bool *is_end_of_word, /* out */ bool *is_error) void cw_clear_receive_buffer(void) int cw_get_receive_buffer_capacity(void) int cw_get_receive_buffer_length(void) void cw_reset_receive(void) void cw_register_keying_callback(void (*callback_func)(void*, int), void *callback_arg) void cw_enable_iambic_curtis_mode_b(void) void cw_disable_iambic_curtis_mode_b(void) int cw_get_iambic_curtis_mode_b_state(void) int cw_notify_keyer_paddle_event(int dot_paddle_state, int dash_paddle_state) int cw_notify_keyer_dot_paddle_event(int dot_paddle_state) int cw_notify_keyer_dash_paddle_event(int dash_paddle_state) void cw_get_keyer_paddles(int *dot_paddle_state, int *dash_paddle_state) void cw_get_keyer_paddle_latches(int *dot_paddle_latch_state, int *dash_pad‐ dle_latch_state) bool cw_is_keyer_busy(void) int cw_wait_for_keyer_element(void) int cw_wait_for_keyer(void) void cw_reset_keyer(void) int cw_notify_straight_key_event(int key_state) int cw_get_straight_key_state(void) bool cw_is_straight_key_busy(void) void cw_reset_straight_key(void) bool cw_is_alsa_possible(const char *device) bool cw_is_console_possible(const char *device) int cw_console_write(cw_gen_t *gen, cw_tone_t *tone) int cw_get_character_count(void) void cw_list_characters(char *list) int cw_get_maximum_representation_length(void) int cw_lookup_character(char c, char *representation) char *cw_character_to_representation(int c) int cw_check_representation(const char *representation) bool cw_representation_is_valid(const char *representation) int cw_lookup_representation(const char *representation, char *c) int cw_representation_to_character(const char *representation) int cw_get_procedural_character_count(void) void cw_list_procedural_characters(char *list) int cw_get_maximum_procedural_expansion_length(void) int cw_lookup_procedural_character(char c, char *expansion, int *is_usually_expanded) int cw_get_maximum_phonetic_length(void) int cw_lookup_phonetic(char c, char *phonetic) bool cw_character_is_valid(char c) bool cw_string_is_valid(const char *string) void cw_debug_flush(cw_debug_t *debug) void cw_set_debug_flags(uint32_t flags) void cw_debug_set_flags(cw_debug_t *debug_object, uint32_t flags) uint32_t cw_get_debug_flags(void) uint32_t cw_debug_get_flags(cw_debug_t *debug_object) bool cw_debug_has_flag(cw_debug_t *debug_object, uint32_t flag) int cw_generator_set_tone_slope(cw_gen_t *gen, int slope_shape, int slope_len) bool cw_is_oss_possible(const char *device) bool cw_is_pa_possible(const char *device) void cw_block_callback(int block) int cw_register_signal_handler(int signal_number, void (*callback_func)(int)) int cw_unregister_signal_handler(int signal_number) int cw_version(void) void cw_license(void) const char *cw_get_audio_system_label(int audio_system) void cw_get_speed_limits(int *min_speed, int *max_speed) void cw_get_frequency_limits(int *min_frequency, int *max_frequency) void cw_get_volume_limits(int *min_volume, int *max_volume) void cw_get_gap_limits(int *min_gap, int *max_gap) void cw_get_tolerance_limits(int *min_tolerance, int *max_tolerance) void cw_get_weighting_limits(int *min_weighting, int *max_weighting) void cw_complete_reset(void) DESCRIPTION libcw is a general purpose CW (Morse code) functions library. It contains routines for converting characters into Morse code representations and back again, for sending Morse code characters, and for receiving characters. It also contains routines to emulate an Iambic Morse keyer, and a straight key. The library can be included in any program that wishes to make use of these features. It forms the heart of three Morse code tutor applications that accompany the package in which it is distributed. See the cw(7) man page for information on Morse code timings, and the dot and dash repre‐ sentations for the various Morse characters. TONE QUEUE libcw contains an inbuilt tone queue. The queue is emptied by background processing, using SIGALRM calls and itimers, so a caller program can continue with other tasks while the library sends tones and keys any external device. As well as being used by the library functions that sound Morse code characters and pro‐ vide a keyer sidetone, the primitive tone queue functions are publicly available to caller programs. CONTROLLING AN EXTERNAL DEVICE libcw may be passed the address of a function that controls external keying. This func‐ tion is called each time the library changes the keying state, either as a result of send‐ ing a Morse character or representation, or as a result of an iambic keyer or straight key state change. The argument passed is a single integer, TRUE for key-down, and FALSE for key-up. libcw calls the external keying function only when the keying state changes. A call is likely each time a tone is taken off the tone queue. SENDING CW CHARACTERS AND STRINGS libcw offers several functions that send individual characters and character strings as Morse code. It also offers functions that allow specialized 'representations' to be sent. A 'representation' is an ASCII string that consists of only the characters '.' and '-'. Characters and strings are converted into representations, and then the correct tones for the dots and dashes in these representations are queued on the tone queue, for action by the background queue emptying process. RECEIVING CW CHARACTERS AND REPRESENTATIONS libcw contains functions to allow it to receive Morse code. To receive, the library must be told when a tone start is detected, and when a tone end is detected. It then deter‐ mines whether the tone was a dot or a dash depending on the timing difference between the two. After the required silence gap has passed, the library may be queried to see what the received representation or character was. Errors in receiving may be detected by means of the flags passed back on receive character functions. IAMBIC KEYER libcw offers functions to simulate an Iambic Morse keyer. The caller program needs to tell the library of paddle state changes. Iambic keyer functions are mutually exclusive with character send and straight key functions. STRAIGHT KEY libcw offers simple functions to allow effective pass-through of straight key information. The caller program needs to tell the library of key state changes. Straight key functions are mutually exclusive with character send and iambic keyer functions. RETURN CODES Some of the library's function return a return code of type int. The return code has two values, as defined in libcw.h: CW_SUCCESS or CW_FAILURE. The two symbolic constants are guaranteed to be identical to boolean true and false. FUNCTIONS The following list describes the functions available to a libcw caller: int cw_generator_new(int audio_system, const char *device) Brief: Create new generator Allocate memory for new generator data structure, set up default values of some of the generator's properties. The function does not start the generator (generator does not produce a sound), you have to use cw_generator_start() for this. Notice that the function doesn't return a generator variable. There is at most one genera‐ tor variable at any given time. You can't have two generators. In some future version of the library the function will return pointer to newly allocated generator, and then you could have as many of them as you want, but not yet. audio_system can be one of following: NULL, console, OSS, ALSA, PulseAudio, soundcard. See "enum cw_audio_systems" in libcw.h for exact names of symbolic constants. Parameter: audio_system - audio system to be used by the generator Parameter: device - name of audio device to be used; if NULL then library will use default device. void cw_generator_delete(void) Brief: Deallocate generator Deallocate/destroy generator data structure created with call to cw_generator_new(). You can't start nor use the generator after the call to this function. int cw_generator_start(void) Brief: Start a generator Start producing tones using generator created with cw_generator_new(). The source of tones is a tone queue associated with the generator. If the tone queue is empty, the generator will wait for new tones to be queued. Returns: CW_FAILURE on errors Returns: CW_SUCCESS on success void cw_generator_stop(void) Brief: Shut down a generator Silence tone generated by generator (level of generated sine wave is set to zero, with falling slope), and shut the generator down. The shutdown does not erase generator's configuration. If you want to have this generator running again, you have to call cw_generator_start(). int cw_set_send_speed(int new_value) Brief: Set sending speed of generator See libcw.h/CW_SPEED_{INITIAL|MIN|MAX} for initial/minimal/maximal value of send speed. errno is set to EINVAL if new_value is out of range. Parameter: new_value - new value of send speed to be assigned to generator Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_set_frequency(int new_value) Brief: Set frequency of generator Set frequency of sound wave generated by generator. The frequency must be within limits marked by CW_FREQUENCY_MIN and CW_FREQUENCY_MAX. See libcw.h/CW_FREQUENCY_{INITIAL|MIN|MAX} for initial/minimal/maximal value of frequency. errno is set to EINVAL if new_value is out of range. Parameter: new_value - new value of frequency to be assigned to generator Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_set_volume(int new_value) Brief: Set volume of generator Set volume of sound wave generated by generator. The volume must be within limits marked by CW_VOLUME_MIN and CW_VOLUME_MAX. Note that volume settings are not fully possible for the console speaker. In this case, volume settings greater than zero indicate console speaker sound is on, and setting volume to zero will turn off console speaker sound. See libcw.h/CW_VOLUME_{INITIAL|MIN|MAX} for initial/minimal/maximal value of volume. errno is set to EINVAL if new_value is out of range. Parameter: new_value - new value of volume to be assigned to generator Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_set_gap(int new_value) Brief: Set sending gap of generator See libcw.h/CW_GAP_{INITIAL|MIN|MAX} for initial/minimal/maximal value of gap. errno is set to EINVAL if new_value is out of range. Notice that this function also sets the same gap value for library's receiver. Parameter: new_value - new value of gap to be assigned to generator Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_set_weighting(int new_value) Brief: Set sending weighting for generator See libcw.h/CW_WEIGHTING_{INITIAL|MIN|MAX} for initial/minimal/maximal value of weighting. errno is set to EINVAL if new_value is out of range. Parameter: new_value - new value of weighting to be assigned for generator Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_get_send_speed(void) Brief: Get sending speed from generator Returns: current value of the generator's send speed int cw_get_frequency(void) Brief: Get frequency from generator Function returns "frequency" parameter of generator, even if the generator is stopped, or volume of generated sound is zero. Returns: current value of generator's frequency int cw_get_volume(void) Brief: Get sound volume from generator Function returns "volume" parameter of generator, even if the generator is stopped. Returns: current value of generator's sound volume int cw_get_gap(void) Brief: Get sending gap from generator Returns: current value of generator's sending gap int cw_get_weighting(void) Brief: Get sending weighting from generator Returns: current value of generator's sending weighting void cw_get_send_parameters(int *dot_usecs, int *dash_usecs, int *end_of_element_usecs, int *end_of_character_usecs, int *end_of_word_usecs, int *additional_usecs, int *adjustment_usecs) Brief: Get timing parameters for sending Return the low-level timing parameters calculated from the speed, gap, tolerance, and weighting set. Parameter values are returned in microseconds. Use NULL for the pointer argument to any parameter value not required. Parameter: dot_usecs Parameter: dash_usecs Parameter: end_of_element_usecs Parameter: end_of_character_usecs Parameter: end_of_word_usecs Parameter: additional_usecs Parameter: adjustment_usecs int cw_send_dot(void) Brief: Low-level primitive for sending a dot mark Low-level primitive function able to play/send single dot mark. The function appends to a tone queue a normal inter-mark gap after the dot mark. Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_send_dash(void) Brief: Low-level primitive for sending a dash mark Low-level primitive function able to play/send single dash mark. The function appends to a tone queue a normal inter-mark gap after the dash mark. Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_send_character_space(void) The function plays space timed to exclude the expected prior dot/dash inter-mark gap. FIXME: fix this description. Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_send_word_space(void) The function sends space timed to exclude both the expected prior dot/dash inter-mark gap and the prior end of character space. FIXME: fix this description. Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_send_representation(const char *representation) Brief: Check, then send the given string as dots and dashes. The representation passed in is assumed to be a complete Morse character; that is, all post-character delays will be added when the character is sent. On success, the routine returns CW_SUCCESS. On failure, it returns CW_FAILURE, with errno set to EINVAL if any character of the representation is invalid, EBUSY if the sound card, console speaker, or keying system is busy, or EAGAIN if the tone queue is full, or if there is insufficient space to queue the tones or the representation. Parameter: representation - representation to send Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_send_representation_partial(const char *representation) Brief: Check, then send the given string as dots and dashes The representation passed in is assumed to be only part of a larger Morse representation; that is, no post-character delays will be added when the character is sent. On success, the routine returns CW_SUCCESS. On failure, it returns CW_FAILURE, with errno set to EINVAL if any character of the representation is invalid, EBUSY if the sound card, console speaker, or keying system is busy, or EAGAIN if the tone queue is full, or if there is insufficient space to queue the tones for the representation. int cw_send_character(char c) Brief: Look up and send a given ASCII character as Morse The end of character delay is appended to the Morse sent. On success the routine returns CW_SUCCESS. On failure the function returns CW_FAILURE and sets errno. errno is set to ENOENT if the given character c is not a valid Morse character. errno is set to EBUSY if current audio sink or keying system is busy. errno is set to EAGAIN if the generator's tone queue is full, or if there is insufficient space to queue the tones for the character. This routine returns as soon as the character has been successfully queued for sending; that is, almost immediately. The actual sending happens in background processing. See cw_wait_for_tone() and cw_wait_for_tone_queue() for ways to check the progress of sending. Parameter: c - character to send Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_send_character_partial(char c) Brief: Look up and send a given ASCII character as Morse code "partial" means that the "end of character" delay is not appended to the Morse code sent by the function, to support the formation of combination characters. On success the function returns CW_SUCCESS. On failure the function returns CW_FAILURE and sets errno. errno is set to ENOENT if the given character c is not a valid Morse character. errno is set to EBUSY if the audio sink or keying system is busy. errno is set to EAGAIN if the tone queue is full, or if there is insufficient space to queue the tones for the charac‐ ter. This routine queues its arguments for background processing. See cw_wait_for_tone() and cw_wait_for_tone_queue() for ways to check the progress of sending. Parameter: c - character to send Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_send_string(const char *string) Brief: Send a given ASCII string in Morse code errno is set to ENOENT if any character in the string is not a valid Morse character. errno is set to EBUSY if audio sink or keying system is busy. errno is set to EAGAIN if the tone queue is full or if the tone queue runs out of space part way through queueing the string. However, an indeterminate number of the characters from the string will have already been queued. For safety, clients can ensure the tone queue is empty before queueing a string, or use cw_send_character() if they need finer control. This routine queues its arguments for background processing, the actual sending happens in background processing. See cw_wait_for_tone() and cw_wait_for_tone_queue() for ways to check the progress of sending. Parameter: string - string to send Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure void cw_reset_send_receive_parameters(void) Brief: Reset send/receive parameters Reset the library speed, frequency, volume, gap, tolerance, weighting, adaptive receive, and noise spike threshold to their initial default values: send/receive speed 12 WPM, vol‐ ume 70 %, frequency 800 Hz, gap 0 dots, tolerance 50 %, and weighting 50 %. const char *cw_get_console_device(void) Brief: Return char string with console device path Returned pointer is owned by library. Returns: char string with current console device path const char *cw_get_soundcard_device(void) Brief: Return char string with soundcard device name/path Returned pointer is owned by library. Returns: char string with current soundcard device name or device path const char *cw_generator_get_audio_system_label(void) Brief: Get a readable label of current audio system The function returns one of following strings: None, Null, Console, OSS, ALSA, PulseAudio, Soundcard Returns: audio system's label int cw_register_tone_queue_low_callback(void (*callback_func)(void*), void *callback_arg, int level) Brief: Register callback for low queue state Register a function to be called automatically by the dequeue routine whenever the tone queue falls to a given level. To be more precise: the callback is called by queue manager if, after dequeueing a tone, the manager notices that tone queue length has become equal or less than level. callback_arg may be used to give a value passed back on callback calls. A NULL function pointer suppresses callbacks. On success, the routine returns CW_SUCCESS. If level is invalid, the routine returns CW_FAILURE with errno set to EINVAL. Any call‐ back supplied will be called in signal handler context. Parameter: callback_func - callback function to be registered Parameter: callback_arg - argument for callback_func to pass return value Parameter: level - low level of queue triggering callback call Returns: CW_SUCCESS on successful registration Returns: CW_FAILURE on failure bool cw_is_tone_busy(void) Brief: Check if tone sender is busy Indicate if the tone sender is busy. Returns: true if there are still entries in the tone queue Returns: false if the queue is empty int cw_wait_for_tone(void) Brief: Wait for the current tone to complete The routine returns CW_SUCCESS on success. If called with SIGALRM blocked, the routine returns CW_FAILURE, with errno set to EDEADLK, to avoid indefinite waits. Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_wait_for_tone_queue(void) Brief: Wait for the tone queue to drain The routine returns CW_SUCCESS on success. If called with SIGALRM blocked, the routine returns false, with errno set to EDEADLK, to avoid indefinite waits. Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_wait_for_tone_queue_critical(int level) Brief: Wait for the tone queue to drain until only as many tones as given in level remain queued This routine is for use by programs that want to optimize themselves to avoid the cleanup that happens when the tone queue drains completely; such programs have a short time in which to add more tones to the queue. The routine returns CW_SUCCESS on success. If called with SIGALRM blocked, the routine returns false, with errno set to EDEADLK, to avoid indefinite waits. Parameter: level - low level in queue, at which to return Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure bool cw_is_tone_queue_full(void) Brief: Indicate if the tone queue is full Returns: true if tone queue is full Returns: false if tone queue is not full int cw_get_tone_queue_capacity(void) Brief: Return the number of entries the tone queue can accommodate int cw_get_tone_queue_length(void) Brief: Return the number of entries currently pending in the tone queue void cw_flush_tone_queue(void) Brief: Cancel all pending queued tones, and return to silence. If there is a tone in progress, the function will wait until this last one has completed, then silence the tones. This function may be called with SIGALRM blocked, in which case it will empty the queue as best it can, then return without waiting for the final tone to complete. In this case, it may not be possible to guarantee silence after the call. void cw_reset_tone_queue(void) Cancel all pending queued tones, reset any queue low callback registered, and return to silence. This function is suitable for calling from an application exit handler. int cw_queue_tone(int usecs, int frequency) Brief: Primitive access to simple tone generation This routine queues a tone of given duration and frequency. The routine returns CW_SUC‐ CESS on success. If usec or frequency are invalid, it returns CW_FAILURE with errno set to EINVAL. If the sound card, console speaker, or keying function are busy, it returns CW_FAILURE with errno set to EBUSY. If the tone queue is full, it returns false with errno set to EAGAIN. Parameter: usecs - duration of queued tone, in microseconds Parameter: frequency - frequency of queued tone Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_set_receive_speed(int new_value) Brief: Set receiving speed of receiver See documentation of cw_set_send_speed() for more information. See libcw.h/CW_SPEED_{INITIAL|MIN|MAX} for initial/minimal/maximal value of receive speed. errno is set to EINVAL if new_value is out of range. errno is set to EPERM if adaptive receive speed tracking is enabled. Parameter: new_value - new value of receive speed to be assigned to receiver Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_get_receive_speed(void) Brief: Get receiving speed from receiver Returns: current value of the receiver's receive speed int cw_set_tolerance(int new_value) Brief: Set tolerance for receiver See libcw.h/CW_TOLERANCE_{INITIAL|MIN|MAX} for initial/minimal/maximal value of tolerance. errno is set to EINVAL if new_value is out of range. Parameter: new_value - new value of tolerance to be assigned to receiver Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_get_tolerance(void) Brief: Get tolerance from receiver Returns: current value of receiver's tolerance void cw_get_receive_parameters(int *dot_usecs, int *dash_usecs, int *dot_min_usecs, int *dot_max_usecs, int *dash_min_usecs, int *dash_max_usecs, int *end_of_element_min_usecs, int *end_of_element_max_usecs, int *end_of_element_ideal_usecs, int *end_of_character_min_usecs, int *end_of_character_max_usecs, int *end_of_character_ideal_usecs, int *adaptive_threshold) Brief: Get timing parameters for receiving, and adaptive threshold Return the low-level timing parameters calculated from the speed, gap, tolerance, and weighting set. Parameter values are returned in microseconds. Use NULL for the pointer argument to any parameter value not required. Parameter: dot_usecs Parameter: dash_usecs Parameter: dot_min_usecs Parameter: dot_max_usecs Parameter: dash_min_usecs Parameter: dash_max_usecs Parameter: end_of_element_min_usecs Parameter: end_of_element_max_usecs Parameter: end_of_element_ideal_usecs Parameter: end_of_character_min_usecs Parameter: end_of_character_max_usecs Parameter: end_of_character_ideal_usecs Parameter: adaptive_threshold int cw_set_noise_spike_threshold(int new_value) Brief: Set noise spike threshold for receiver Set the period shorter than which, on receive, received marks are ignored. This allows the "receive mark" functions to apply noise canceling for very short apparent marks. For useful results the value should never exceed the dot length of a dot at maximum speed: 20000 microseconds (the dot length at 60WPM). Setting a noise threshold of zero turns off receive mark noise canceling. The default noise spike threshold is 10000 microseconds. errno is set to EINVAL if new_value is out of range. Parameter: new_value - new value of noise spike threshold to be assigned to receiver Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_get_noise_spike_threshold(void) Brief: Get noise spike threshold from receiver See documentation of cw_set_noise_spike_threshold() for more information Returns: current value of receiver's threshold void cw_get_receive_statistics(double *dot_sd, double *dash_sd, double *element_end_sd, double *character_end_sd) Brief: Calculate and return receiver's timing statistics These statistics may be used to obtain a measure of the accuracy of received CW. The val‐ ues dot_sd and dot_sd contain the standard deviation of dot and dash lengths from the ideal values, and element_end_sd and element_end_sd the deviations for inter element and inter character spacing. Statistics are held for all timings in a 256 element circular buffer. If any statistic cannot be calculated, because no records for it exist, the returned value is 0.0. Use NULL for the pointer argument to any statistic not required. Parameter: dot_sd Parameter: dash_sd Parameter: element_end_sd Parameter: character_end_sd void cw_reset_receive_statistics(void) Brief: Clear the receive statistics buffer Clear the receive statistics buffer by removing all records from it and returning it to its initial default state. void cw_enable_adaptive_receive(void) Brief: Enable adaptive receive speed tracking If adaptive speed tracking is enabled, the receive functions will attempt to automatically adjust the receive speed setting to match the speed of the incoming Morse code. If it is disabled, the receive functions will use fixed speed settings, and reject incoming Morse which is not at the expected speed. Adaptive speed tracking uses a moving average length of the past N marks as its baseline for tracking speeds. The default state is adaptive speed tracking disabled. void cw_disable_adaptive_receive(void) Brief: Disable adaptive receive speed tracking See documentation of cw_enable_adaptive_receive() for more information bool cw_get_adaptive_receive_state(void) Brief: Get adaptive receive speed tracking flag The function returns state of "adaptive receive enabled" flag. See documentation of cw_enable_adaptive_receive() for more information Returns: true if adaptive speed tracking is enabled Returns: false otherwise int cw_start_receive_tone(const struct timeval *timestamp) Brief: Signal beginning of receive mark Called on the start of a receive mark. If the timestamp is NULL, the current timestamp is used as beginning of mark. The function should be called by client application when pressing a key down (closing a circuit) has been detected by client application. On error the function returns CW_FAILURE, with errno set to ERANGE if the call is directly after another cw_start_receive_tone() call or if an existing received character has not been cleared from the buffer, or EINVAL if the timestamp passed in is invalid. Parameter: timestamp - time stamp of "key down" event Returns: CW_SUCCESS on success Returns: CW_FAILURE otherwise (with errno set) int cw_end_receive_tone(const struct timeval *timestamp) Brief: Signal end of mark The function should be called by client application when releasing a key (opening a cir‐ cuit) has been detected by client application. If the timestamp is NULL, the current time is used as timestamp of end of mark. On success, the routine adds a dot or dash to the receiver's representation buffer, and returns CW_SUCCESS. On failure, it returns CW_FAIURE, with errno set to: ERANGE if the call was not preceded by a cw_start_receive_tone() call, EINVAL if the timestamp passed in is not valid, ENOENT if the mark length was out of bounds for the permissible dot and dash lengths and fixed speed receiving is selected, ENOMEM if the receiver's representation buffer is full, EAGAIN if the mark was shorter than the threshold for noise and was therefore ignored. Parameter: timestamp - time stamp of "key up" event Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_receive_buffer_dot(const struct timeval *timestamp) Brief: Add a dot to the receiver's representation buffer Documentation for both cw_receive_buffer_dot() and cw_receive_buffer_dash(): Since we can't add a mark to the buffer without any accompanying timing information, the functions accepts timestamp of the "end of mark" event. If the timestamp is NULL, the current timestamp is used. These routines are for client code that has already determined whether a dot or dash was received by a method other than calling the routines cw_start_receive_tone() and cw_end_receive_tone(). On success, the relevant mark is added to the receiver's representation buffer. On failure, the routines return CW_FAILURE, with errno set to ERANGE if preceded by a cw_start_receive_tone() call with no matching cw_end_receive_tone() or if an error condi‐ tion currently exists within the receiver's buffer, or ENOMEM if the receiver's represen‐ tation buffer is full. Parameter: timestamp - timestamp of "end of dot" event Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_receive_buffer_dash(const struct timeval *timestamp) Brief: Add a dash to the receiver's representation buffer See documentation of cw_receive_buffer_dot() for more information. Parameter: timestamp - timestamp of "end of dash" event Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_receive_representation(const struct timeval *timestamp, /* out */ char *representation, /* out */ bool *is_end_of_word, /* out */ bool *is_error) Brief: Get the current buffered representation from the receiver's representation buffer On success the function fills in representation with the contents of the current represen‐ tation buffer and returns CW_SUCCESS. On failure, it returns CW_FAILURE and sets errno to: ERANGE if not preceded by a cw_end_receive_tone() call, a prior successful cw_receive_representation call, or a prior cw_receive_buffer_dot or cw_receive_buffer_dash, EINVAL if the timestamp passed in is invalid, EAGAIN if the call is made too early to determine whether a complete representa‐ tion has yet been placed in the buffer (that is, less than the end-of-character gap period elapsed since the last cw_end_receive_tone() or cw_receive_buffer_dot/dash call). This is not a *hard* error, just an information that the caller should try to get the representa‐ tion later. is_end_of_word indicates that the space after the last mark received is longer that the end-of-character gap, so it must be qualified as end-of-word gap. is_error indicates that the representation was terminated by an error condition. TODO: the function should be called cw_receiver_poll_representation(). The function is called periodically (poll()-like function) by client code in hope that at some attempt receiver will be ready to pass representation. The attempt succeeds only if data stream is in "space" state. To mark end of the space, client code has to provide a timestamp (or pass NULL timestamp, the function will get time stamp at function call). The receiver needs to know the "end of space" event - thus the timestamp parameter. Parameter: timestamp - timestamp of event that ends "end-of-character" gap or "end-of- word" gap Parameter: representation - buffer for representation (output parameter) Parameter: is_end_of_word - buffer for "is end of word" state (output parameter) Parameter: is_error - buffer for "error" state (output parameter) Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_receive_character(const struct timeval *timestamp, /* out */ char *c, /* out */ bool *is_end_of_word, /* out */ bool *is_error) Brief: Get a current character Function returns the character currently stored in receiver's representation buffer. On success the function returns CW_SUCCESS, and fills c with the contents of the current representation buffer, translated into a character. On failure the function returns CW_FAILURE, with errno set to: ERANGE if not preceded by a cw_end_receive_tone() call, a prior successful cw_receive_character() call, or a cw_receive_buffer_dot() or cw_receive_buffer_dash() call, EINVAL if the timestamp passed in is invalid, or EAGAIN if the call is made too early to determine whether a complete character has yet been placed in the buffer (that is, less than the end-of-character gap period elapsed since the last cw_end_receive_tone() or cw_receive_buffer_dot/dash call). ENOENT if character stored in receiver cannot be recognized as valid is_end_of_word indicates that the space after the last mark received is longer that the end-of-character gap, so it must be qualified as end-of-word gap. is_error indicates that the character was terminated by an error condition. Parameter: timestamp - timestamp of event that ends end-of-character gap or end-of-word gap Parameter: c - buffer for character (output parameter) Parameter: is_end_of_word - buffer for "is end of word" state (output parameter) Parameter: is_error - buffer for "error" state (output parameter) Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure void cw_clear_receive_buffer(void) Brief: Clear receiver's representation buffer Clears the receiver's representation buffer, resets receiver's internal state. This pre‐ pares the receiver to receive marks and spaces again. This routine must be called after successful, or terminating, cw_receive_representation() or cw_receive_character() calls, to clear the states and prepare the buffer to receive more marks and spaces. int cw_get_receive_buffer_capacity(void) Brief: Get the number of elements (dots/dashes) the receiver's buffer can accommodate The maximum number of elements written out by cw_receive_representation() is the capacity + 1, the extra character being used for the terminating NUL. Returns: number of elements that can be stored in receiver's representation buffer int cw_get_receive_buffer_length(void) Brief: Get the number of elements (dots/dashes) currently pending in the cw_receiver's representation buffer Returns: number of elements in receiver's representation buffer void cw_reset_receive(void) Brief: Clear receive data Clear the receiver's representation buffer, statistics, and any retained receiver's state. This function is suitable for calling from an application exit handler. void cw_register_keying_callback(void (*callback_func)(void*, int), void *callback_arg) Brief: Register external callback function for keying Register a callback_func function that should be called when a state of a key changes from "key open" to "key closed", or vice-versa. The first argument passed to the registered callback function is the supplied call‐ back_arg, if any. The second argument passed to registered callback function is the key state: CW_KEY_STATE_CLOSED (one/true) for "key closed", and CW_KEY_STATE_OPEN (zero/false) for "key open". Calling this routine with a NULL function address disables keying callbacks. Any callback supplied will be called in signal handler context (??). Parameter: callback_func - callback function to be called on key state changes Parameter: callback_arg - first argument to callback_func void cw_enable_iambic_curtis_mode_b(void) Brief: Enable iambic Curtis mode B Normally, the iambic keying functions will emulate Curtis 8044 Keyer mode A. In this mode, when both paddles are pressed together, the last dot or dash being sent on release is completed, and nothing else is sent. In mode B, when both paddles are pressed together, the last dot or dash being sent on release is completed, then an opposite element is also sent. Some operators prefer mode B, but timing is more critical in this mode. The default mode is Curtis mode A. void cw_disable_iambic_curtis_mode_b(void) See documentation of cw_enable_iambic_curtis_mode_b() for more information int cw_get_iambic_curtis_mode_b_state(void) See documentation of cw_enable_iambic_curtis_mode_b() for more information int cw_notify_keyer_paddle_event(int dot_paddle_state, int dash_paddle_state) Brief: Inform about changed state of iambic keyer's paddles Function informs the library that the iambic keyer paddles have changed state. The new paddle states are recorded, and if either transition from false to true, paddle latches, for iambic functions, are also set. On success, the routine returns CW_SUCCESS. On failure, it returns CW_FAILURE, with errno set to EBUSY if the tone queue or straight key are using the sound card, console speaker, or keying system. If appropriate, this routine starts the keyer functions sending the relevant element. Element send and timing occurs in the background, so this routine returns almost immedi‐ ately. See cw_keyer_element_wait() and cw_keyer_wait() for details about how to check the current status of iambic keyer background processing. Parameter: dot_paddle_state Parameter: dash_paddle_state Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_notify_keyer_dot_paddle_event(int dot_paddle_state) Brief: Change state of dot paddle Alter the state of just one of the two iambic keyer paddles. The other paddle state of the paddle pair remains unchanged. See cw_notify_keyer_paddle_event() for details of iambic keyer background processing, and how to check its status. Parameter: dot_paddle_state int cw_notify_keyer_dash_paddle_event(int dash_paddle_state) See documentation of cw_notify_keyer_dot_paddle_event() for more information void cw_get_keyer_paddles(int *dot_paddle_state, int *dash_paddle_state) Brief: Get the current saved states of the two paddles Parameter: dot_paddle_state Parameter: dash_paddle_state void cw_get_keyer_paddle_latches(int *dot_paddle_latch_state, int *dash_pad‐ dle_latch_state) Brief: Get the current states of paddle latches Function returns the current saved states of the two paddle latches. A paddle latches is set to true when the paddle state becomes true, and is cleared if the paddle state is false when the element finishes sending. Parameter: dot_paddle_latch_state Parameter: dash_paddle_latch_state bool cw_is_keyer_busy(void) Brief: Check if a keyer is busy Returns: true if keyer is busy Returns: false if keyer is not busy int cw_wait_for_keyer_element(void) Brief: Wait for end of element from the keyer Waits until the end of the current element, dot or dash, from the keyer. On error the function returns CW_FAILURE, with errno set to EDEADLK if SIGALRM is blocked. Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_wait_for_keyer(void) Brief: Wait for the current keyer cycle to complete The routine returns CW_SUCCESS on success. On error, it returns CW_FAILURE, with errno set to EDEADLK if SIGALRM is blocked or if either paddle state is true. Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure void cw_reset_keyer(void) Brief: Reset iambic keyer data Clear all latches and paddle states of iambic keyer, return to Curtis 8044 Keyer mode A, and return to silence. This function is suitable for calling from an application exit handler. int cw_notify_straight_key_event(int key_state) Brief: Inform the library that the straight key has changed state This routine returns CW_SUCCESS on success. On error, it returns CW_FAILURE, with errno set to EBUSY if the tone queue or iambic keyer are using the sound card, console speaker, or keying control system. If key_state indicates no change of state, the call is ignored. key_state may be either CW_KEY_STATE_OPEN (false) or CW_KEY_STATE_CLOSED (true). Parameter: key_state - state of straight key int cw_get_straight_key_state(void) Brief: Get saved state of straight key Returns the current saved state of the straight key. Returns: CW_KEY_STATE_CLOSED (true) if the key is down Returns: CW_KEY_STATE_OPEN (false) if the key up bool cw_is_straight_key_busy(void) Brief: Check if the straight key is busy This routine is just a pseudonym for cw_get_straight_key_state(), and exists to fill a hole in the API naming conventions. Returns: true if the straight key is busy Returns: false if the straight key is not busy void cw_reset_straight_key(void) Brief: Clear the straight key state, and return to silence This function is suitable for calling from an application exit handler. bool cw_is_alsa_possible(const char *device) Brief: Check if it is possible to open ALSA output Function first tries to load ALSA library, and then does a test opening of ALSA output, but it closes it before returning. Parameter: device - name of ALSA device to be used; if NULL then library will use default device. Returns: true if opening ALSA output succeeded; Returns: false if opening ALSA output failed; bool cw_is_console_possible(const char *device) Brief: Check if it is possible to open console output Function does a test opening and test writing to console device, but it closes it before returning. The function tests that the given console file exists, and that it will accept the KIOC‐ SOUND ioctl. It unconditionally returns false on platforms that do no support the KIOC‐ SOUND ioctl. Call to ioctl will fail if calling code doesn't have root privileges. This is the only place where we ask if KIOCSOUND is defined, so client code must call this function whenever it wants to use console output, as every other function called to per‐ form console operations will happily assume that it is allowed to perform such operations. Parameter: device - name of console device to be used; if NULL then library will use default device. Returns: true if opening console output succeeded; Returns: false if opening console output failed; int cw_console_write(cw_gen_t *gen, cw_tone_t *tone) Brief: Pseudo-device for playing sound with console Function behaving like a device, to which one does a blocking write. It generates sound with parameters (frequency and duration) specified in tone.. After playing X microseconds of tone it returns. It is intended to behave like a blocking write() function. Parameter: gen - current generator Parameter: tone - tone to play with generator Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_get_character_count(void) Brief: Return the number of characters present in character lookup table Return the number of characters that are known to libcw. The number includes: · ASCII 7bit letters, · numerals, · punctuation, · ISO 8859-1 accented characters, · ISO 8859-2 accented characters, · non-standard procedural signal extensions to standard CW characters. Returns: number of characters known to libcw void cw_list_characters(char *list) Brief: Get list of characters present in character lookup table Function provides a string containing all of the characters represented in library's lookup table. The list includes: · ASCII 7bit letters, · numerals, · punctuation, · ISO 8859-1 accented characters, · ISO 8859-2 accented characters, · non-standard procedural signal extensions to standard CW characters. list should be allocated and managed by caller. The length of list must be at least one greater than the number of characters represented in the character lookup table, returned by cw_get_character_count(). Parameter: list - pointer to space to be filled by function int cw_get_maximum_representation_length(void) Brief: Get length of the longest representation Function returns the string length of the longest representation in the character lookup table. Returns: a positive number - length of the longest representation int cw_lookup_character(char c, char *representation) Brief: Get representation of a given character The function is depreciated, use cw_character_to_representation() instead. Return the string representation (shape) of a given Morse code character c. The routine returns CW_SUCCESS on success, and fills in the string pointer (representa‐ tion) passed in. On failure, it returns CW_FAILURE and sets errno to ENOENT, indicating that the character c could not be found. The length of representation buffer must be at least one greater than the length of long‐ est representation held in the character lookup table. The largest value of length is returned by cw_get_maximum_representation_length(). Parameter: c - character to look up Parameter: representation - pointer to space for representation of character Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure char *cw_character_to_representation(int c) Brief: Get representation of a given character On success return representation of a given character. Returned pointer is owned by call‐ er of the function. On failure function returns NULL and sets errno: ENOENT indicates that the character could not be found. ENOMEM indicates that character has been found, but function failed to strdup() representation. Parameter: c - character to look up Returns: pointer to freshly allocated representation on success Returns: NULL on failure int cw_check_representation(const char *representation) Brief: Check if representation of a character is valid This function is depreciated, use cw_representation_is_valid() instead. Check that the given string is a valid Morse representation. A valid string is one com‐ posed of only "." and "-" characters. If representation is invalid, function returns CW_FAILURE and sets errno to EINVAL. Parameter: representation - representation of a character to check Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure bool cw_representation_is_valid(const char *representation) Brief: Check if representation of a character is valid Check that the given string is a valid Morse representation. A valid string is one com‐ posed of only "." and "-" characters. This means that the function checks only if repre‐ sentation is error-free, and not whether the representation represents existing/defined character. If representation is invalid, function returns false and sets errno to EINVAL. Parameter: representation - representation of a character to check Returns: true on success Returns: false on failure int cw_lookup_representation(const char *representation, char *c) Brief: Get the character represented by a given Morse representation This function is depreciated, use cw_representation_to_character() instead. Function checks representation, and if it is valid and represents a known character, func‐ tion returns CW_SUCCESS. Additionally, if c is non-NULL, function puts the looked up char‐ acter in c. c should be allocated by caller. Function assumes that c being NULL pointer is a valid situation, and can return CW_SUCCESS in such situation. On error, function returns CW_FAILURE. errno is set to EINVAL if any character of the rep‐ resentation is invalid, or ENOENT to indicate that the character represented by represen‐ tation could not be found. Parameter: representation - representation of a character to look up Parameter: c - location where to put looked up character Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure int cw_representation_to_character(const char *representation) Brief: Return the character represented by a given Morse representation Function checks representation, and if it is valid and represents a known character, func‐ tion returns the character (a non-zero value). On error, function returns zero. errno is set to EINVAL if any character of the represen‐ tation is invalid, or ENOENT to indicate that the character represented by representation could not be found. Parameter: representation - representation of a character to look up Returns: non-zero character on success Returns: zero on failure int cw_get_procedural_character_count(void) Brief: Get number of procedural signals Returns: the number of characters represented in the procedural signal expansion lookup table void cw_list_procedural_characters(char *list) Brief: Get list of characters for which procedural expansion is available Function returns into list a string containing all of the Morse characters for which pro‐ cedural expansion is available. The length of list must be at least by one greater than the number of characters represented in the procedural signal expansion lookup table, returned by cw_get_procedural_character_count(). list is managed by caller Parameter: list - space for returned characters int cw_get_maximum_procedural_expansion_length(void) Brief: Get length of the longest procedural expansion Function returns the string length of the longest expansion in the procedural signal expansion table. Returns: length int cw_lookup_procedural_character(char c, char *expansion, int *is_usually_expanded) Brief: Get the string expansion of a given Morse code procedural signal character On success the function - fills expansion with the string expansion of a given Morse code procedural signal character c; - sets is_usuall_expanded to true as a display hint for the caller; - returns CW_SUCCESS. Both expansion and expansion must be allocated and managed by caller. They can be NULL, then the function won't attempt to use them. The length of expansion must be at least by one greater than the longest expansion held in the procedural signal character lookup table, as returned by cw_get_maximum_procedur‐ al_expansion_length(). If procedural signal character c cannot be found, the function sets errno to ENOENT and returns CW_FAILURE. Parameter: c - character to look up Parameter: expansion - output, space to fill with expansion of the character Parameter: is_usually_expanded - visual hint Returns: CW_FAILURE on failure (errno is set to ENOENT) Returns: CW_SUCCESS on success int cw_get_maximum_phonetic_length(void) Brief: Get maximum length of a phonetic Returns: the string length of the longest phonetic in the phonetics lookup table int cw_lookup_phonetic(char c, char *phonetic) Brief: Get the phonetic of a given character On success the routine fills in the string pointer passed in with the phonetic of given character c. The length of phonetic must be at least one greater than the longest phonetic held in the phonetic lookup table, as returned by cw_get_maximum_phonetic_length(). If character cannot be found, the function sets errno to ENOENT. Parameter: c - character to look up Parameter: phonetic - output, space for phonetic of a character Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure bool cw_character_is_valid(char c) Brief: Checks that the given character is validly sendable in Morse Function sets errno to ENOENT on failure. Parameter: c - character to check Returns: CW_SUCCESS if character is valid Returns: CW_FAILURE if character is invalid bool cw_string_is_valid(const char *string) Brief: Validate a string Check that each character in the given string is valid and can be sent by libcw as a Morse character. Function sets errno to EINVAL on failure Parameter: string - string to check Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure void cw_debug_flush(cw_debug_t *debug) Brief: Write all events from the debug object to a file Function writes all events stored in the debug object to file associated with the object, and removes the events. List of events is preceded with "FLUSH START0 line, and followed by "FLUSH END0 line. Parameter: debug - debug object void cw_set_debug_flags(uint32_t flags) Brief: Set a value of internal debug flags variable Assign specified value to library's internal debug flags variable. Note that this func‐ tion doesn't *append* given flag to the variable, it erases existing value and assigns new one. Use cw_get_debug_flags() if you want to OR new flag with existing ones. Parameter: new_value - new value to be assigned to the library void cw_debug_set_flags(cw_debug_t *debug_object, uint32_t flags) uint32_t cw_get_debug_flags(void) Brief: Get current library's debug flags Function returns value of library's internal debug variable. Returns: value of library's debug flags variable uint32_t cw_debug_get_flags(cw_debug_t *debug_object) bool cw_debug_has_flag(cw_debug_t *debug_object, uint32_t flag) Brief: Check if given debug flag is set Function checks if a specified debug flag is set in internal variable of libcw library. Parameter: flag - flag to be checked. Returns: true if given flag is set Returns: false if given flag is not set int cw_generator_set_tone_slope(cw_gen_t *gen, int slope_shape, int slope_len) Brief: Set parameters of tones generated by generator Most of variables related to slope of tones is in tone data type, but there are still some variables that are generator-specific, as they are common for all tones. This function sets two of these variables. A: If you pass to function conflicting values of slope_shape and slope_len, the function will return CW_FAILURE. These conflicting values are rectangular slope shape and larger than zero slope length. You just can't have rectangular slopes that have non-zero length. B: If you pass to function '-1' as value of both slope_shape and slope_len, the function won't change any of the related two generator's parameters. C1: If you pass to function '-1' as value of either slope_shape or slope_len, the function will attempt to set only this generator's parameter that is different than '-1'. C2: However, if selected slope shape is rectangular, function will set generator's slope length to zero, even if value of slope_len is '-1'. D: Notice that the function allows non-rectangular slope shape with zero length of the slopes. The slopes will be non-rectangular, but just unusually short. The function should be called every time one of following parameters change: · shape of slope, · length of slope, · generator's sample rate, · generator's volume. There are four supported shapes of slopes: · linear (the only one supported by libcw until version 4.1.1), · raised cosine (supposedly the most desired shape), · sine, · rectangular. Use CW_TONE_SLOPE_SHAPE_* symbolic names as values of slope_shape. FIXME: first argument of this public function is gen, but no function provides access to generator variable. Parameter: gen - generator for which to set tone slope parameters Parameter: slope_shape - shape of slope: linear, raised cosine, sine, rectangular Parameter: slope_len - length of slope [microseconds] Returns: CW_SUCCESS on success Returns: CW_FAILURE on failure bool cw_is_oss_possible(const char *device) Brief: Check if it is possible to open OSS output Function does a test opening and test configuration of OSS output, but it closes it before returning. Parameter: device - name of OSS device to be used; if NULL then library will use default device. Returns: true if opening OSS output succeeded; Returns: false if opening OSS output failed; bool cw_is_pa_possible(const char *device) Brief: Check if it is possible to open PulseAudio output Function first tries to load PulseAudio library, and then does a test opening of PulseAu‐ dio output, but it closes it before returning. Parameter: device - sink device, NULL for default PulseAudio device Returns: true if opening PulseAudio output succeeded; Returns: false if opening PulseAudio output failed; void cw_block_callback(int block) Brief: Block the callback from being called Function blocks the callback from being called for a critical section of caller code if block is true, and unblocks the callback if block is false. Function works by blocking SIGALRM; a block should always be matched by an unblock, other‐ wise the tone queue will suspend forever. Parameter: block - pass 1 to block SIGALRM, and 0 to unblock it int cw_register_signal_handler(int signal_number, void (*callback_func)(int)) Brief: Register a signal handler and optional callback function for given signal number On receipt of that signal, all library features will be reset to their default states. Following the reset, if callback_func is a function pointer, the function is called; if it is SIG_DFL, the library calls exit(); and if it is SIG_IGN, the library returns from the signal handler. This is a convenience function for clients that need to clean up library on signals, with either exit, continue, or an additional function call; in effect, a wrapper round a restricted form of sigaction. The signal_number argument indicates which signal to catch. On problems errno is set to EINVAL if signal_number is invalid or if a handler is already installed for that signal, or to the sigaction error code. Parameter: signal_number Parameter: callback_func Returns: CW_SUCCESS - if the signal handler installs correctly Returns: CW_FAILURE - on errors or problems int cw_unregister_signal_handler(int signal_number) Brief: Unregister a signal handler interception Function removes a signal handler interception previously registered with cw_register_sig‐ nal_handler(). Parameter: signal_number Returns: true if the signal handler uninstalls correctly Returns: false otherwise (with errno set to EINVAL or to the sigaction error code) int cw_version(void) Brief: Return version number of libcw library Return the version number of the library. Version numbers (major and minor) are returned as an int, composed of major_version << 16 | minor_version. Returns: library's major and minor version number encoded as single int void cw_license(void) Brief: Print libcw's license text to stdout Function prints information about libcw version, followed by short text presenting libcw's copyright and license notice. const char *cw_get_audio_system_label(int audio_system) Brief: Get a readable label of given audio system The function returns one of following strings: None, Null, Console, OSS, ALSA, PulseAudio, Soundcard Returned pointer is owned and managed by the library. TODO: change the declaration to "const char *const cw_get_audio_system_label(...)"? Parameter: audio_system - ID of audio system Returns: audio system's label void cw_get_speed_limits(int *min_speed, int *max_speed) Brief: Get speed limits Get (through function's arguments) limits on speed of morse code that can be generated by generator. See CW_SPEED_MIN and CW_SPEED_MAX in libcw.h for values. Parameter: min_speed - minimal allowed speed Parameter: max_speed - maximal allowed speed void cw_get_frequency_limits(int *min_frequency, int *max_frequency) Brief: Get frequency limits Get (through function's arguments) limits on frequency that can be generated by generator. See CW_FREQUENCY_MIN and CW_FREQUENCY_MAX in libcw.h for values. Parameter: min_frequency - minimal allowed frequency Parameter: max_frequency - maximal allowed frequency void cw_get_volume_limits(int *min_volume, int *max_volume) Brief: Get volume limits Get (through function's arguments) limits on volume of sound generated by generator. See CW_VOLUME_MIN and CW_VOLUME_MAX in libcw.h for values. Parameter: min_volume - minimal allowed volume Parameter: max_volume - maximal allowed volume void cw_get_gap_limits(int *min_gap, int *max_gap) Brief: Get gap limits Get (through function's arguments) limits on gap in cw signal generated by generator. See CW_GAP_MIN and CW_GAP_MAX in libcw.h for values. Parameter: min_gap - minimal allowed gap Parameter: max_gap - maximal allowed gap void cw_get_tolerance_limits(int *min_tolerance, int *max_tolerance) Brief: Get tolerance limits Get (through function's arguments) limits on "tolerance" parameter of generator. See CW_TOLERANCE_MIN and CW_TOLERANCE_MAX in libcw.h for values. Parameter: min_tolerance - minimal allowed tolerance Parameter: max_tolerance - maximal allowed tolerance void cw_get_weighting_limits(int *min_weighting, int *max_weighting) Brief: Get weighting limits Get (through function's arguments) limits on "weighting" parameter of generator. See CW_WEIGHTING_MIN and CW_WEIGHTING_MAX in libcw.h for values. Parameter: min_weighting - minimal allowed weighting Parameter: max_weighting - maximal allowed weighting void cw_complete_reset(void) Brief: Reset all library features to their default states Clears the tone queue, receive buffers and retained state information, any current keyer activity, and any straight key activity, returns to silence, and closes soundcard and con‐ sole devices. This function is suitable for calling from an application exit handler.

NOTES

Despite the fact that this manual page constantly and consistently refers to Morse code elements as dots and dashes, DO NOT think in these terms when trying to learn Morse code. Always think of them as 'dit's and 'dah's. libcw uses system itimers for its internal timing. On most UNIX flavours, itimers are not guaranteed to signal a program exactly at the specified time, and they generally offer a resolution only as good as the normal system 'clock tick' resolution. An itimer SIGALRM usually falls on a system clock tick, making it accurate to no better than 10mS on a typi‐ cal 100Hz kernel. The effect of this is that an itimer period is generally either exactly as specified, or, more likely, slightly longer. At higher WPM settings, the cumulative effect of this affects timing accuracy, because at higher speeds, there are fewer 10mS clock ticks in a dot period. For example, at 12 WPM, the dot length is 100mS, enough to contain five ker‐ nel clock ticks; at 60 WPM, the dot length is 20mS, or just two kernel clock ticks. So at higher speeds, the effect of itimer resolutions becomes more pronounced.

SEE ALSO

Man pages for cw(7,LOCAL), cw(1,LOCAL), cwgen(1,LOCAL), cwcp(1,LOCAL), and xcwcp(1,LOCAL).
libcw ver. 6.6.1 CW Tutor Package LIBCW(3)
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