unw_get_proc_info - Man Page

#include <libunwind.h>

int unw_get_proc_info(unw_cursor_t *cp, unw_proc_info_t *pip);

The unw_get_proc_info() routine returns auxiliary  information about the procedure that created the stack frame  identified by argument cp. The pip argument is a pointer  to a structure of type unw_proc_info_t which is used to  return the information. The unw_proc_info_t has the  following members:

unw_word_t start_ip

The address of the first  instruction of the procedure. If this address cannot be determined  (e.g., due to lack of unwind information), the start_ip member is cleared to 0.

unw_word_t end_ip

The address of the first  instruction beyond the end of the procedure. If this address  cannot be determined (e.g., due to lack of unwind information),  the end_ip member is cleared to 0.

unw_word_t lsda

The address of the  language-specific data area (LSDA). This area normally contains  language-specific information needed during exception handling. If  the procedure has no such area, this member is cleared to 0.

unw_word_t handler

The address of the exception  handler routine. This is sometimes called the personality routine. If the procedure does not define  a personality routine, the handler member is cleared to 0.

unw_word_t gp

The global pointer of the  procedure. On platforms that do not use a global pointer, this  member may contain an undefined value. On all other platforms, it  must be set either to the correct global pointer value of the  procedure or to 0 if the proper global pointer cannot be  obtained for some reason.

unw_word_t flags

A set of flags. There are  currently no target-independent flags. For the IA-64 target, the  flag UNW_PI_FLAG_IA64_RBS_SWITCH is set if the  procedure may switch the register backing store.

int format

The format of the unwind info for this  procedure. If the unwind info consists of dynamic procedure info,  format is equal to UNW_INFO_FORMAT_DYNAMIC. If the  unwind info consists of a (target-specific) unwind table, it is  equal to UNW_INFO_FORMAT_TABLE. All other values are  reserved for future use by libunwind. This member exists  for use by the find_proc_info() callback (see  unw_create_addr_space(3libunwind)). The  unw_get_proc_info() routine  may return an undefined value in this member.

int unwind_info_size

The size of the unwind info  in bytes. This member exists for use by the  find_proc_info() callback (see  unw_create_addr_space(3libunwind)). The  unw_get_proc_info() routine  may return an undefined value in this member.

void *unwind_info

The pointer to the unwind info.  If no unwind info is available, this member must be set to  NULL. This member exists for use by the  find_proc_info() callback (see  unw_create_addr_space(3libunwind)). The  unw_get_proc_info() routine  may return an undefined value in this member.

Note that for the purposes of libunwind, the code of a  procedure is assumed to occupy a single, contiguous range of  addresses. For this reason, it is always possible to describe the  extent of a procedure with the start_ip and end_ip members. If a single function/routine is split into multiple,  discontiguous pieces, libunwind will treat each piece as a  separate procedure.

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

unw_get_proc_info() is thread safe. If cursor cp is  in the local address space, this routine is also safe to use from a  signal handler.

UNW_EUNSPEC

An unspecified error occurred.

UNW_ENOINFO

Libunwind was unable to locate  unwind info for the procedure.

UNW_EBADVERSION

The unwind info for the procedure has  version or format that is not understood by libunwind.

In addition, unw_get_proc_info() may return any error  returned by the access_mem() callback (see  unw_create_addr_space(3libunwind)).

libunwind(3libunwind), unw_create_addr_space(3libunwind), unw_get_proc_name(3libunwind)

David Mosberger-Tang
Email: dmosberger@gmail.com
WWW: http://www.nongnu.org/libunwind/.