UNW_GETCONTEXT(3) Programming Library UNW_GETCONTEXT(3)NAMEunw_getcontext-- get initial machine-state
SYNOPSIS
#include <libunwind.h>
int unw_getcontext(unw_context_t *ucp);
DESCRIPTION
The unw_getcontext() routine initializes the context structure pointed
to by ucp with the machine-state of the call-site. The exact set of
registers stored by unw_getcontext() is platform-specific, but, in gen‐
eral, at least all preserved (``callee-saved'') and all frame-related
registers, such as the stack-pointer, will be stored.
This routine is normally implemented as a macro and applications should
not attempt to take its address.
PLATFORM-SPECIFIC NOTES
On IA-64, unw_context_t has a layout that is compatible with that of
ucontext_t and such structures can be initialized with getcontext()
instead of unw_getcontext(). However, the reverse is not true and it
is not safe to use structures initialized by unw_getcontext() in places
where a structure initialized by getcontext() is expected. The reason
for this asymmetry is that unw_getcontext() is optimized for maximum
performance and does not, for example, save the signal mask.
RETURN VALUE
On successful completion, unw_getcontext() returns 0. Otherwise, a
value of -1 is returned.
THREAD AND SIGNAL SAFETYunw_getcontext() is thread-safe as well as safe to use from a signal
handler.
SEE ALSOlibunwind(3), unw_init_local(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 30 March 2004 UNW_GETCONTEXT(3)
