unw_get_proc_info −− get info on current procedure
#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() call−back (see unw_create_addr_space(3)). 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() call−back (see unw_create_addr_space(3)). 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() call−back (see unw_create_addr_space(3)). 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() call−back (see unw_create_addr_space(3)).
libunwind(3), unw_create_addr_space(3), unw_get_proc_name(3)
David
Mosberger−Tang
Email: [email protected]
WWW: http://www.nongnu.org/libunwind/.