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STRTOUL, STRTOULL, STRTOUQ - reference manual online

Convert a string to an unsigned long integer.

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2015-08-08
STRTOUL(3)                          Linux Programmer's Manual                          STRTOUL(3)

NAME strtoul, strtoull, strtouq - convert a string to an unsigned long integer
SYNOPSIS #include <stdlib.h> unsigned long int strtoul(const char *nptr, char **endptr, int base); unsigned long long int strtoull(const char *nptr, char **endptr, int base); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): strtoull(): _XOPEN_SOURCE >= 600 || _BSD_SOURCE || _SVID_SOURCE || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L; or cc -std=c99
DESCRIPTION The strtoul() function converts the initial part of the string in nptr to an unsigned long int value according to the given base, which must be between 2 and 36 inclusive, or be the special value 0. The string may begin with an arbitrary amount of white space (as determined by isspace(3)) followed by a single optional '+' or '-' sign. If base is zero or 16, the string may then include a "0x" prefix, and the number will be read in base 16; otherwise, a zero base is taken as 10 (decimal) unless the next character is '0', in which case it is taken as 8 (octal). The remainder of the string is converted to an unsigned long int value in the obvious man‐ ner, stopping at the first character which is not a valid digit in the given base. (In bases above 10, the letter 'A' in either uppercase or lowercase represents 10, 'B' repre‐ sents 11, and so forth, with 'Z' representing 35.) If endptr is not NULL, strtoul() stores the address of the first invalid character in *endptr. If there were no digits at all, strtoul() stores the original value of nptr in *endptr (and returns 0). In particular, if *nptr is not '\0' but **endptr is '\0' on return, the entire string is valid. The strtoull() function works just like the strtoul() function but returns an unsigned long long int value.
RETURN VALUE The strtoul() function returns either the result of the conversion or, if there was a leading minus sign, the negation of the result of the conversion represented as an unsigned value, unless the original (nonnegated) value would overflow; in the latter case, strtoul() returns ULONG_MAX and sets errno to ERANGE. Precisely the same holds for str‐ toull() (with ULLONG_MAX instead of ULONG_MAX).
ERRORS EINVAL (not in C99) The given base contains an unsupported value. ERANGE The resulting value was out of range. The implementation may also set errno to EINVAL in case no conversion was performed (no digits seen, and 0 returned).
ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌─────────────────────────────────┬───────────────┬────────────────┐ │Interface │ Attribute │ Value │ ├─────────────────────────────────┼───────────────┼────────────────┤ │strtoul(), strtoull(), strtouq() │ Thread safety │ MT-Safe locale │ └─────────────────────────────────┴───────────────┴────────────────┘
CONFORMING TO strtoul(): POSIX.1-2001, POSIX.1-2008, C89, C99 SVr4. strtoull(): POSIX.1-2001, POSIX.1-2008, C99.
NOTES Since strtoul() can legitimately return 0 or ULONG_MAX (ULLONG_MAX for strtoull()) on both success and failure, the calling program should set errno to 0 before the call, and then determine if an error occurred by checking whether errno has a nonzero value after the call. In locales other than the "C" locale, other strings may be accepted. (For example, the thousands separator of the current locale may be supported.) BSD also has u_quad_t strtouq(const char *nptr, char **endptr, int base); with completely analogous definition. Depending on the wordsize of the current architec‐ ture, this may be equivalent to strtoull() or to strtoul(). Negative values are considered valid input and are silently converted to the equivalent unsigned long int value.
EXAMPLE See the example on the strtol(3) manual page; the use of the functions described in this manual page is similar.
SEE ALSO atof(3), atoi(3), atol(3), strtod(3), strtol(3)
COLOPHON This page is part of release 4.04 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at http://www.kernel.org/doc/man-pages/.
GNU 2015-08-08 STRTOUL(3)
This manual Reference Other manuals
strtoul(3) referred by a64l(3) | ascii2binary(1) | atof(3) | atoi(3) | collectd.conf(5) | explain(1) | explain(3) | explain_lca2010(1) | explain_strtoul(3) | explain_strtoul_or_die(3) | explain_strtoull(3) | explain_strtoull_or_die(3) | hfst-reweight(1) | scanf(3) | strtod(3) | strtoimax(3) | strtol(3) | strtonum(3) | SWISH-CONFIG(1) | uni2ascii(1)
refer to atof(3) | atoi(3) | attributes(7) | feature_test_macros(7) | isalpha(3) | strtod(3) | strtol(3)