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dwarf_init(3) [freebsd man page]

DWARF_INIT(3)						   BSD 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(). RETURN VALUES
These functions return the following values: [DW_DLV_OK] This return value indicates a successful return. [DW_DLV_ERROR] The operation failed. [DW_DLV_NO_ENTRY] The object specified by arguments fd or elf did not contain debug information. IMPLEMENTATION NOTES
The current implementation does not support access modes DW_DLC_RDWR and DW_DLC_WRITE. 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) BSD
November 9, 2011 BSD

Check Out this Related Man Page

DWARF_NEXT_TYPES_SECTION(3)				   BSD Library Functions Manual 			       DWARF_NEXT_TYPES_SECTION(3)

NAME
dwarf_next_types_section -- step through .debug_types sections in a debug context LIBRARY
DWARF Access Library (libdwarf, -ldwarf) SYNOPSIS
#include <libdwarf.h> int dwarf_next_types_section(Dwarf_Debug dbg, Dwarf_Error *err); DESCRIPTION
Function dwarf_next_types_section() steps through the ``.debug_types'' sections found in a debug context. Argument dbg should reference a DWARF debug context allocated using dwarf_init(3). Argument err should point to a location that will hold an error descriptor in case of an error. When a DWARF debug context is allocated using dwarf_init(3), an internal pointer associated with the context will point to the first ``.debug_types'' section present in the debug object. When the application calls function dwarf_next_types_section(), this internal pointer will move to the next ``.debug_types'' section present. On stepping past the last ``.debug_types'' section left in the debug context, func- tion dwarf_next_types_section() returns DW_DLV_NO_ENTRY. The next call to the function will restart from the first ``.debug_types'' section in the debug context. Application code should call function dwarf_next_cu_header_c(3) to iterate though the type units associated with the current ``.debug_types'' section. RETURN VALUES
On success, function dwarf_next_types_section() returns DW_DLV_OK. In case of an error, it returns DW_DLV_ERROR and sets argument err. When there are no more ``.debug_types'' sections left to traverse, it returns DW_DLV_NO_ENTRY. COMPATIBILITY
This function is an extension to the DWARF(3) API. ERRORS
The dwarf_next_types_section() function may fail with the following errors: [DW_DLE_ARGUMENT] Argument dbg was NULL. EXAMPLES
To iterate though every type unit in all the ``.debug_types'' sections found in a debug context: Dwarf_Debug dbg; Dwarf_Sig8 sig8; Dwarf_Unsigned typeoff; Dwarf_Error de; ... allocate dbg using dwarf_init() etc ... do { while ((ret = dwarf_next_cu_header_c(dbg, 0, NULL, NULL, NULL, NULL, NULL, NULL, &sig8, &typeoff, NULL, &de)) == DW_DLV_OK) { /* Access DIEs etc ... */ } } while (dwarf_next_types_section(dbg, &de) == DW_DLV_OK); SEE ALSO
dwarf(3), dwarf_init(3), dwarf_next_cu_header_c(3) BSD
December 20, 2014 BSD

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