FreeBSD manual
download PDF document: dwarf_init.3.pdf
DWARF_INIT(3) FreeBSD Library Functions Manual DWARF_INIT(3)
NAME
dwarf_init, dwarf_elf_init - allocate a DWARF debug descriptor
LIBRARY
DWARF Access Library (libdwarf, -ldwarf)
SYNOPSIS
#include <libdwarf.h>
int
dwarf_init(int fd, int mode, Dwarf_Handler errhand, Dwarf_Ptr errarg,
Dwarf_Debug *ret, Dwarf_Error *err);
in
dwarf_elf_init(Elf *elf, int mode, Dwarf_Handler errhand,
Dwarf_Ptr errarg, Dwarf_Debug *ret, Dwarf_Error *err);
DESCRIPTION
These functions allocate and return a Dwarf_Debug instance for the object
denoted by argument fd or elf. This instance would be used for
subsequent access to debugging information in the object by other
functions in the DWARF(3) library.
For function dwarf_init(), argument fd denotes an open file descriptor
referencing a compilation object. Function dwarf_init() implicitly
allocates an Elf descriptor for argument fd.
For function dwarf_elf_init(), argument elf denotes a descriptor returned
by elf_begin(3) or elf_memory(3).
Argument mode specifies the access mode desired. It should be at least
as permissive as the mode with which the file descriptor fd or the ELF
descriptor elf was created with. Legal values for argument mode are:
DW_DLC_RDWR Permit reading and writing of DWARF information.
DW_DLC_READ Operate in read-only mode.
DW_DLC_WRITE Permit writing of DWARF information.
Argument errhand denotes a function to be called in case of an error. If
this argument is NULL then a default error handling scheme is used. See
dwarf(3) for a description of the error handling scheme used by the
DWARF(3) library.
Argument errarg is passed to the error handler function denoted by
argument errhand when it is invoked.
Argument ret points to the memory location that will hold a Dwarf_Debug
reference on a successful call these functions.
Argument err references a memory location that would hold a Dwarf_Error
descriptor in case of an error.
Memory Management
The Dwarf_Debug instance returned by these functions should be freed
using dwarf_finish().
IMPLEMENTATION NOTES
[DW_DLV_ERROR] The operation failed.
[DW_DLV_NO_ENTRY] The object specified by arguments fd or elf did not
contain debug information.
EXAMPLES
To initialize a Dwarf_Debug instance from a open file descriptor
referencing an ELF object, and with the default error handler, use:
Dwarf_Error err;
Dwarf_Debug dbg;
if (dwarf_init(fd, DW_DLC_READ, NULL, NULL, &dbg, &err) !=
DW_DLV_OK)
errx(EXIT_FAILURE, "dwarf_init: %s", dwarf_errmsg(err));
SEE ALSO
dwarf(3), dwarf_errmsg(3), dwarf_finish(3), dwarf_get_elf(3),
elf_begin(3), elf_memory(3)
FreeBSD 14.0-RELEASE-p11 November 9, 2011 FreeBSD 14.0-RELEASE-p11