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unw_get_reg(3) [debian man page]

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). 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'') 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 single word. See unw_get_fpreg(3) for a way to read registers which do not fit this constraint. 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_cre- ate_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: dmosberger@gmail.com WWW: http://www.nongnu.org/libunwind/. Programming Library 16 August 2007 UNW_GET_REG(3)

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UNW_INIT_LOCAL(3)					       Programming Library						 UNW_INIT_LOCAL(3)

NAME
unw_init_local -- initialize cursor for local unwinding SYNOPSIS
#include <libunwind.h> int unw_init_local(unw_cursor_t *c, unw_context_t *ctxt); DESCRIPTION
The unw_init_local() routine initializes the unwind cursor pointed to by c with the machine-state in the context structure pointed to by ctxt. As such, the machine-state pointed to by ctxt identifies the initial stack frame at which unwinding starts. The machine-state must remain valid for the duration for which the cursor c is in use. The unw_init_local() routine can be used only for unwinding in the address space of the current process (i.e., for local unwinding). For all other cases, unw_init_remote() must be used instead. From a behavioral point of view, the call: ret = unw_init_local(&cursor, &ucontext); is equivalent to: ret = unw_init_remote(&cursor, unw_local_addr_space, &ucontext); However, unwind performance may be better when using unw_init_local(). Also, unw_init_local() is available even when UNW_LOCAL_ONLY has been defined before including <libunwind.h>, whereas unw_init_remote() is not. RETURN VALUE
On successful completion, unw_init_local() returns 0. Otherwise the negative value of one of the error-codes below is returned. THREAD AND SIGNAL SAFETY
unw_init_local() is thread-safe as well as safe to use from a signal handler. ERRORS
UNW_EINVAL unw_init_local() was called in a version of libunwind which supports remote unwinding only (this normally happens when calling unw_init_local() for a cross-platform version of libunwind). UNW_EUNSPEC An unspecified error occurred. UNW_EBADREG A register needed by unw_init_local() wasn't accessible. SEE ALSO
libunwind(3), unw_init_remote(3) AUTHOR
David Mosberger-Tang Email: dmosberger@gmail.com WWW: http://www.nongnu.org/libunwind/. Programming Library 16 August 2007 UNW_INIT_LOCAL(3)

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