UNW_SET_REG(3) Programming Library UNW_SET_REG(3)NAMEunw_set_reg-- set register contents
SYNOPSIS
#include <libunwind.h>
int unw_set_reg(unw_cursor_t *cp, unw_regnum_t reg, unw_word_t val);
DESCRIPTION
The unw_set_reg() routine sets the value of register reg in the stack
frame identified by cursor cp to the value passed in val.
The register numbering is target-dependent and described in separate
manual pages (e.g., libunwind-ia64(3) for the IA-64 target). Further‐
more, the exact set of accessible registers may depend on the type of
frame that cp is referring to. For ordinary stack frames, it is nor‐
mally possible to access only the preserved (``callee-saved'') regis‐
ters 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_set_reg() can only write the contents of registers whose
values fit in a single word. See unw_set_fpreg(3) for a way to write
registers which do not fit this constraint.
RETURN VALUE
On successful completion, unw_set_reg() returns 0. Otherwise the nega‐
tive value of one of the error-codes below is returned.
THREAD AND SIGNAL SAFETYunw_set_reg() is thread-safe as well as safe to use from a signal han‐
dler.
ERRORS
UNW_EUNSPEC
An unspecified error occurred.
UNW_EBADREG
An attempt was made to write a register that is either invalid
or not accessible in the current frame.
UNW_EREADONLY
An attempt was made to write to a read-only register.
In addition, unw_set_reg() may return any error returned by the
access_mem(), access_reg(), and access_fpreg() call-backs (see unw_cre‐
ate_addr_space(3)).
SEE ALSOlibunwind(3), libunwind-ia64(3), unw_get_reg(3), unw_is_sig‐
nal_frame(3), unw_set_fpreg(3)AUTHOR
David Mosberger-Tang
Hewlett-Packard Labs
Palo-Alto, CA 94304
Email: davidm@hpl.hp.com
WWW: http://www.hpl.hp.com/research/linux/libunwind/.
Programming Library 05 August 2004 UNW_SET_REG(3)
