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dwarf_get_abbrev_entry(3) [freebsd 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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DWARF_GET_FDE_LIST(3)					   BSD Library Functions Manual 				     DWARF_GET_FDE_LIST(3)

NAME
dwarf_get_fde_list -- retrieve frame information LIBRARY
DWARF Access Library (libdwarf, -ldwarf) SYNOPSIS
#include <libdwarf.h> int dwarf_get_fde_list(Dwarf_Debug dbg, Dwarf_Cie **cie_list, Dwarf_Signed *cie_count, Dwarf_Fde **fde_list, Dwarf_Signed *fde_count, Dwarf_Error *err); int dwarf_get_fde_list_eh(Dwarf_Debug dbg, Dwarf_Cie **cie_list, Dwarf_Signed *cie_count, Dwarf_Fde **fde_list, Dwarf_Signed *fde_count, Dwarf_Error *err); DESCRIPTION
These functions retrieve frame related information for the specified DWARF debug context. Function dwarf_get_fde_list() retrieves frame information from the DWARF section named ``.debug_frame''. For objects containing GNU style C++ exception handling information, the function dwarf_get_fde_list_eh() retrieves frame information from the section named ``.eh_frame''. Frame information is returned using opaque descriptors of type Dwarf_Cie and Dwarf_Fde. Applications need to use the other frame related functions in the DWARF(3) API set to retrieve the information contained in these descriptors. Argument dbg should reference a DWARF debug context allocated using dwarf_init(3). Argument cie_list should point to a location that will be set to a pointer to an array of Dwarf_Cie descriptors. Argument cie_count should point to a location that will be set to the number of Dwarf_Cie descriptors returned. Argument fde_list should point to a location that will be set to a pointer to an array of Dwarf_Fde descriptors. Argument fde_count should point to a location that will be set to the number of Dwarf_Fde descriptors returned. If argument err is not NULL, it will be used to store error information in case of an error. Memory Management The memory areas used for the arrays returned in arguments cie_list and fde_list are owned by the DWARF Access Library (libdwarf, -ldwarf). Application code should not attempt to directly free these areas. Portable applications should instead use the dwarf_fde_cie_list_dealloc(3) function to indicate that these memory areas may be freed. RETURN VALUES
On success, these functions returns DW_DLV_OK. They return DW_DLV_NO_ENTRY if there is no frame information associated with the given DWARF debug context. In case of an error, they return DW_DLV_ERROR and set the argument err. ERRORS
These functions may fail with the following errors: [DW_DLE_ARGUMENT] One of the arguments dbg, cie_list, cie_count, fde_list or fde_count was NULL. [DW_DLE_NO_ENTRY] There is no frame information associated with the giving DWARF debug context. EXAMPLE
To obtain frame information from the ``.debug_frame'' section, use: Dwarf_Debug dbg; Dwarf_Cie *cie_list, cie; Dwarf_Fde *fde_list, fde; Dwarf_Off fde_offset, cie_offset; Dwarf_Unsigned func_len, fde_length, fde_instlen; Dwarf_Signed cie_count, fde_count, cie_index; Dwarf_Addr low_pc; Dwarf_Ptr fde_addr, fde_inst, cie_inst; Dwarf_Error de; int i; if (dwarf_get_fde_list(dbg, &cie_list, &cie_count, &fde_list, &fde_count, &de) != DW_DLV_OK) { errx(EXIT_FAILURE, "dwarf_get_fde_list failed: %s", dwarf_errmsg(de)); } for (i = 0; i < fde_count; i++) { if (dwarf_get_fde_n(fde_list, i, &fde, &de) != DW_DLV_OK) { warnx("dwarf_get_fde_n failed: %s", dwarf_errmsg(de)); continue; } if (dwarf_get_cie_of_fde(fde, &cie, &de) != DW_DLV_OK) { warnx("dwarf_get_fde_n failed: %s", dwarf_errmsg(de)); continue; } if (dwarf_get_fde_range(fde, &low_pc, &func_len, &fde_addr, &fde_length, &cie_offset, &cie_index, &fde_offset, &de) != DW_DLV_OK) { warnx("dwarf_get_fde_range failed: %s", dwarf_errmsg(de)); continue; } if (dwarf_get_fde_instr_bytes(fde, &fde_inst, &fde_instlen, &de) != DW_DLV_OK) { warnx("dwarf_get_fde_instr_bytes failed: %s", dwarf_errmsg(de)); continue; } /* ... Use the retrieved frame information ... */ } /* Indicate that the returned arrays may be freed. */ dwarf_fde_cie_list_dealloc(dbg, cie_list, cie_count, fde_list, fde_count); SEE ALSO
dwarf(3), dwarf_get_cie_index(3), dwarf_get_cie_of_fde(3), dwarf_get_fde_at_pc(3), dwarf_get_fde_instr_bytes(3), dwarf_get_fde_n(3), dwarf_get_fde_range(3), dwarf_fde_cie_list_dealloc(3), dwarf_set_frame_cfa_value(3), dwarf_set_frame_rule_table_size(3), dwarf_set_frame_rule_initial_value(3), dwarf_set_frame_same_value(3), dwarf_set_frame_undefined_value(3) BSD
November 9, 2011 BSD

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