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

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16 August 2007
UNW_GET_REG(3) Programming Library UNW_GET_REG(3)

NAME

unw_get_reg -- get register contents

SYNOPSIS

#include <libunwind.h> int unw_get_reg(unw_cursor_t *cp, unw_regnum_t reg, unw_word_t *valp);

DESCRIPTION

The unw_get_reg() routine reads the value of register reg in the stack frame identified by cursor cp and stores the value in the word pointed to by valp. The register numbering is target-dependent and described in separate manual pages (e.g., libunwind-ia64(3) for the IA-64 target). Furthermore, the exact set of accessible regis‐ ters may depend on the type of frame that cp is referring to. For ordinary stack frames, it is normally possible to access only the preserved (``callee-saved'') registers and frame-related registers (such as the stack-pointer). However, for signal frames (see unw_is_signal_frame(3)), it is usually possible to access all registers. Note that unw_get_reg() can only read the contents of registers whose values fit in a sin‐ gle word. See unw_get_fpreg(3) for a way to read registers which do not fit this con‐ straint.

RETURN VALUE

On successful completion, unw_get_reg() returns 0. Otherwise the negative value of one of the error-codes below is returned.

THREAD AND SIGNAL SAFETY

unw_get_reg() is thread-safe as well as safe to use from a signal handler.

ERRORS

UNW_EUNSPEC An unspecified error occurred. UNW_EBADREG An attempt was made to read a register that is either invalid or not accessible in the current frame. In addition, unw_get_reg() may return any error returned by the access_mem(), access_reg(), and access_fpreg() call-backs (see unw_create_addr_space(3)).

SEE ALSO

libunwind(3), libunwind-ia64(3), unw_get_fpreg(3), unw_is_signal_frame(3), unw_set_reg(3)

AUTHOR

David Mosberger-Tang Email: @gmail.com WWW: http://www.nongnu.org/libunwind/.
Programming Library 16 August 2007 UNW_GET_REG(3)
This manual Reference Other manuals
unw_get_reg(3) referred by libunwind(3) | unw_get_fpreg(3) | unw_is_fpreg(3) | unw_is_signal_frame(3) | unw_set_reg(3)
refer to libunwind(3) | libunwind-ia64(3) | unw_create_addr_space(3) | unw_get_fpreg(3) | unw_is_signal_frame(3) | unw_set_reg(3)
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