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dwarf_get_abbrev(3) [freebsd man page]

DWARF_GET_ABBREV(3)					   BSD Library Functions Manual 				       DWARF_GET_ABBREV(3)

NAME
dwarf_get_abbrev -- retrieve abbreviation information LIBRARY
DWARF Access Library (libdwarf, -ldwarf) SYNOPSIS
#include <libdwarf.h> int dwarf_get_abbrev(Dwarf_Debug dbg, Dwarf_Unsigned offset, Dwarf_Abbrev *ret_abbrev, Dwarf_Unsigned *length, Dwarf_Unsigned *attr_count, Dwarf_Error *err); DESCRIPTION
Function dwarf_get_abbrev() retrieves information about an abbreviation from the DWARF abbreviations section, ``.debug_abbrev''. Abbrevia- tion information is returned using an opaque descriptor of type Dwarf_Abbrev. The returned Dwarf_Abbrev descriptor may then be passed to the other abbreviation related APIs in the DWARF(3) API to retrieve specific information about the abbreviation. Argument dbg should reference a DWARF debug context allocated using dwarf_init(3). Argument offset should be an offset, relative to the ``.debug_abbrev'' section, to the start of an abbreviation entry. Argument ret_abbrev should point to a location that will hold a pointer to the returned Dwarf_Abbrev descriptor. Argument length should point to a location that will hold the number of bytes used by the abbrevation in the DWARF ``.debug_abbrev'' section. Argument attr_count should point to a location that will hold the number of attributes in the abbrevation. If argument err is not NULL, it will be used to store error information in case of an error. Memory Management The memory area used for the Dwarf_Abbrev descriptor returned in argument ret_abbrev is allocated by the DWARF Access Library (libdwarf, -ldwarf). Application code should use function dwarf_dealloc() with the allocation type DW_DLA_ABBREV to free the memory area when the Dwarf_Abbrev descriptor is no longer needed. Application Programming Notes The last abbreviation entry in a standard DWARF abbreviation section will have a special length value of 1. RETURN VALUES
Function dwarf_get_abbrev() returns DW_DLV_OK when it succeeds. It returns DW_DLV_NO_ENTRY if there is no abbreviation information at offset offset. In case of an error, it returns DW_DLV_ERROR and sets the argument err. ERRORS
Function dwarf_get_abbrev() can fail with: [DW_DLE_ARGUMENT] One of the arguments dbg, ret_abbrev, length or attr_count was NULL. [DW_DLE_NO_ENTRY] There is no abbreviation information at offset offset. EXAMPLE
To loop through all the abbreviation information associated with a DWARF debug context, use: Dwarf_Debug dbg; Dwarf_Abbrev ab; Dwarf_Off aboff; Dwarf_Unsigned length, attr_count; Dwarf_Half tag; Dwarf_Error de; int ret; while ((ret = dwarf_next_cu_header(dbg, NULL, NULL, &aboff, NULL, NULL, &de)) == DW_DLV_OK) { while ((ret = dwarf_get_abbrev(re->dbg, aboff, &ab, &length, &attr_count, &de)) == DW_DLV_OK) { if (length == 1) /* Last entry. */ break; aboff += length; if (dwarf_get_abbrev_tag(ab, &tag, &de) != DW_DLV_OK) { warnx("dwarf_get_abbrev_tag failed: %s", dwarf_errmsg(de)); continue; } if (ret != DW_DLV_OK) warnx("dwarf_get_abbrev: %s", dwarf_errmsg(de)); } if (ret == DW_DLV_ERROR) warnx("dwarf_next_cu_header: %s", dwarf_errmsg(de)); SEE ALSO
dwarf(3), dwarf_dealloc(3), dwarf_get_abbrev_tag(3), dwarf_get_abbrev_code(3), dwarf_get_abbrev_children_flag(3), dwarf_get_abbrev_entry(3) BSD
March 27, 2011 BSD

Check Out this Related Man Page

DWARF_GET_ABBREV_ENTRY(3)				   BSD Library Functions Manual 				 DWARF_GET_ABBREV_ENTRY(3)

NAME
dwarf_get_abbrev_entry -- retrieve attribute information from an abbreviation descriptor LIBRARY
DWARF Access Library (libdwarf, -ldwarf) SYNOPSIS
#include <libdwarf.h> int dwarf_get_abbrev_entry(Dwarf_Abbrev abbrev, Dwarf_Signed ndx, Dwarf_Half *code, Dwarf_Signed *form, Dwarf_Off *offset, Dwarf_Error *err); DESCRIPTION
Function dwarf_get_abbrev_entry() retrieves attribute information from a DWARF abbreviation descriptor. Argument abbrev should be a valid abbreviation descriptor, as returned by function dwarf_get_abbrev(3). Argument ndx specifies the 0-based index of the attribute. The total count of the attributes contained in the abbreviation entry can be retrieved using the function dwarf_get_abbrev(3). Argument code should point to a location which will hold a returned attribute code. Argument form should point to a location which will hold the returned form of the attribute. Argument offset should point to a location which will hold a returned offset, relative to the ``.debug_abbrev'' section, for the specified attribute. If argument err is not NULL, it will be used to return an error descriptor in case of an error. RETURN VALUES
Function dwarf_get_abbrev_entry() returns DW_DLV_OK when it succeeds. It returns DW_DLV_NO_ENTRY if the attribute index specified by argu- ment ndx is out of range. In case of an error, it returns DW_DLV_ERROR and sets the argument err. ERRORS
Function dwarf_get_abbrev_entry() can fail with: [DW_DLE_ARGUMENT] One of the arguments abbrev, code, form or offset was NULL. [DW_DLE_NO_ENTRY] The attribute index specified by argument ndx was out of range. EXAMPLE
To loop through all the attribute entries contained in the abbreviation section, use: Dwarf_Debug dbg; Dwarf_Abbrev ab; Dwarf_Off aboff, atoff; Dwarf_Signed form; Dwarf_Half attr; Dwarf_Unsigned length, attr_count; Dwarf_Error de; int i, ret; /* ...allocate 'dbg' using dwarf_init(3) ... */ while ((ret = dwarf_next_cu_header(dbg, NULL, NULL, &aboff, NULL, NULL, &de)) == DW_DLV_OK) { while ((ret = dwarf_get_abbrev(dbg, aboff, &ab, &length, &attr_count, &de)) == DW_DLV_OK) { if (length == 1) /* Last entry. */ break; aboff += length; for (i = 0; (Dwarf_Unsigned) i < attr_count; i++) { if (dwarf_get_abbrev_entry(ab, i, &attr, &form, &atoff, &de) != DW_DLV_OK) { warnx("dwarf_get_abbrev_entry failed:" " %s", dwarf_errmsg(de)); continue; } /* .. use the retrieved information ... */ } } if (ret != DW_DLV_OK) warnx("dwarf_get_abbrev: %s", dwarf_errmsg(de)); } if (ret == DW_DLV_ERROR) warnx("dwarf_next_cu_header: %s", dwarf_errmsg(de)); SEE ALSO
dwarf(3), dwarf_get_abbrev(3) BSD
April 02, 2011 BSD

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