1.\" $NetBSD: dwarf_get_abbrev_entry.3,v 1.4 2020/11/26 22:51:35 jkoshy Exp $ 2.\" 3.\" Copyright (c) 2011 Kai Wang 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" Id: dwarf_get_abbrev_entry.3 3644 2018-10-15 19:55:01Z jkoshy 28.\" 29.Dd April 02, 2011 30.Dt DWARF_GET_ABBREV_ENTRY 3 31.Os 32.Sh NAME 33.Nm dwarf_get_abbrev_entry 34.Nd retrieve attribute information from an abbreviation descriptor 35.Sh LIBRARY 36.Lb libdwarf 37.Sh SYNOPSIS 38.In libdwarf.h 39.Ft int 40.Fo dwarf_get_abbrev_entry 41.Fa "Dwarf_Abbrev abbrev" 42.Fa "Dwarf_Signed ndx" 43.Fa "Dwarf_Half *code" 44.Fa "Dwarf_Signed *form" 45.Fa "Dwarf_Off *offset" 46.Fa "Dwarf_Error *err" 47.Fc 48.Sh DESCRIPTION 49Function 50.Fn dwarf_get_abbrev_entry 51retrieves attribute information from a DWARF abbreviation descriptor. 52.Pp 53Argument 54.Ar abbrev 55should be a valid abbreviation descriptor, as returned by function 56.Xr dwarf_get_abbrev 3 . 57.Pp 58Argument 59.Ar ndx 60specifies the 0-based index of the attribute. 61The total count of the attributes contained in the abbreviation 62entry can be retrieved using the function 63.Xr dwarf_get_abbrev 3 . 64.Pp 65Argument 66.Ar code 67should point to a location which will hold a returned 68attribute code. 69.Pp 70Argument 71.Ar form 72should point to a location which will hold the returned 73form of the attribute. 74.Pp 75Argument 76.Ar offset 77should point to a location which will hold a returned offset, relative 78to the 79.Dq ".debug_abbrev" 80section, for the specified attribute. 81.Pp 82If argument 83.Ar err 84is not NULL, it will be used to return an error descriptor in case 85of an error. 86.Sh RETURN VALUES 87Function 88.Fn dwarf_get_abbrev_entry 89returns 90.Dv DW_DLV_OK 91when it succeeds. 92It returns 93.Dv DW_DLV_NO_ENTRY 94if the attribute index specified by argument 95.Ar ndx 96is out of range. 97In case of an error, it returns 98.Dv DW_DLV_ERROR 99and sets the argument 100.Ar err . 101.Sh EXAMPLES 102To loop through all the attribute entries contained in the 103abbreviation section, use: 104.Bd -literal -offset indent 105Dwarf_Debug dbg; 106Dwarf_Abbrev ab; 107Dwarf_Off aboff, atoff; 108Dwarf_Signed form; 109Dwarf_Half attr; 110Dwarf_Unsigned length, attr_count; 111Dwarf_Error de; 112int i, ret; 113 114/* ...allocate 'dbg' using dwarf_init(3) ... */ 115 116while ((ret = dwarf_next_cu_header(dbg, NULL, NULL, &aboff, 117 NULL, NULL, &de)) == DW_DLV_OK) { 118 while ((ret = dwarf_get_abbrev(dbg, aboff, &ab, &length, 119 &attr_count, &de)) == DW_DLV_OK) { 120 if (length == 1) /* Last entry. */ 121 break; 122 aboff += length; 123 for (i = 0; (Dwarf_Unsigned) i < attr_count; i++) { 124 if (dwarf_get_abbrev_entry(ab, i, 125 &attr, &form, &atoff, &de) != DW_DLV_OK) { 126 warnx("dwarf_get_abbrev_entry failed:" 127 " %s", dwarf_errmsg(de)); 128 continue; 129 } 130 /* .. use the retrieved information ... */ 131 } 132 } 133 134 if (ret != DW_DLV_OK) 135 warnx("dwarf_get_abbrev: %s", dwarf_errmsg(de)); 136} 137 138if (ret == DW_DLV_ERROR) 139 warnx("dwarf_next_cu_header: %s", dwarf_errmsg(de)); 140.Ed 141.Sh ERRORS 142Function 143.Fn dwarf_get_abbrev_entry 144can fail with: 145.Bl -tag -width ".Bq Er DW_DLE_NO_ENTRY" 146.It Bq Er DW_DLE_ARGUMENT 147One of the arguments 148.Ar abbrev , 149.Ar code , 150.Ar form 151or 152.Ar offset 153was NULL. 154.It Bq Er DW_DLE_NO_ENTRY 155The attribute index specified by argument 156.Ar ndx 157was out of range. 158.El 159.Sh SEE ALSO 160.Xr dwarf 3 , 161.Xr dwarf_get_abbrev 3 162