1.\" $NetBSD: dwarf_next_cu_header.3,v 1.2 2014/03/09 16:58:04 christos Exp $ 2.\" 3.\" Copyright (c) 2010 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_next_cu_header.3 2074 2011-10-27 03:34:33Z jkoshy 28.\" 29.Dd July 24, 2010 30.Os 31.Dt DWARF_NEXT_CU_HEADER 3 32.Sh NAME 33.Nm dwarf_next_cu_header , 34.Nm dwarf_next_cu_header_b 35.Nd step through compilation units in a DWARF debug context 36.Sh LIBRARY 37.Lb libdwarf 38.Sh SYNOPSIS 39.In libdwarf.h 40.Ft int 41.Fo dwarf_next_cu_header 42.Fa "Dwarf_Debug dbg" 43.Fa "Dwarf_Unsigned *cu_length" 44.Fa "Dwarf_Half *cu_version" 45.Fa "Dwarf_Off *cu_abbrev_offset" 46.Fa "Dwarf_Half *cu_pointer_size" 47.Fa "Dwarf_Unsigned *cu_next_offset" 48.Fa "Dwarf_Error *err" 49.Fc 50.Ft int 51.Fo dwarf_next_cu_header_b 52.Fa "Dwarf_Debug dbg" 53.Fa "Dwarf_Unsigned *cu_length" 54.Fa "Dwarf_Half *cu_version" 55.Fa "Dwarf_Off *cu_abbrev_offset" 56.Fa "Dwarf_Half *cu_pointer_size" 57.Fa "Dwarf_Half *cu_offset_size" 58.Fa "Dwarf_Half *cu_extension_size" 59.Fa "Dwarf_Unsigned *cu_next_offset" 60.Fa "Dwarf_Error *err" 61.Fc 62.Sh DESCRIPTION 63These functions are used to step through compilation unit contexts 64associated with a DWARF debug context, optionally returning information 65about the unit. 66.Pp 67Function 68.Fn dwarf_next_cu_header_b 69is the API recommended for new application code. 70Argument 71.Ar dbg 72should reference a DWARF debug context allocated using 73.Xr dwarf_init 3 . 74Argument 75.Ar cu_length 76should point to a location that will be set to the 77length of the compilation unit. 78Argument 79.Ar cu_version 80should point to a location that will be set to the 81version number for the compilation unit. 82Argument 83.Ar cu_abbrev_offset 84should point to a location that will be set to the 85starting offset (in the 86.Dq .debug_abbrev 87section) of the set of debugging information entry abbreviations 88associated with this compilation unit. 89Argument 90.Ar cu_pointer_size 91should point to a location that will be set to the 92size in bytes of an address for the machine architecture of the 93underlying object being debugged. 94Argument 95.Ar cu_offset_size 96should point to a location that will be set to the 97size in bytes for a DWARF offset in the compilation unit. 98Argument 99.Ar cu_extension_size 100is only needed for processing MIPS/IRIX objects that use 101a non-standard DWARF format. 102It should point to a location that will be set to 4 for normal 103objects and to 0 for non-standard ones. 104Argument 105.Ar cu_next_offset 106should point to a location that will be set to the 107offset of the next compilation unit header in the 108.Dq \&.debug_info 109section. 110Argument 111.Ar err 112should point to a location that will hold an error descriptor in case 113of an error. 114.Pp 115Function 116.Fn dwarf_next_cu_header 117is less general than 118.Fn dwarf_next_cu_header_b , 119and is deprecated for use by new application code. 120Argument 121.Ar dbg 122should reference a DWARF debug context allocated using 123.Xr dwarf_init 3 . 124Argument 125.Ar cu_length 126should point to a location that will be set to the 127length of the compilation unit. 128Argument 129.Ar cu_version 130should point to a location that will be set to the 131version number for the compilation unit. 132Argument 133.Ar cu_abbrev_offset 134should point to a location that will be set to the 135starting offset in the 136.Dq .debug_abbrev 137section of the set of debugging information entry abbreviations 138associated with this compilation unit. 139Argument 140.Ar cu_pointer_size 141should point to a location that will be set to the 142size of an address in bytes for the machine architecture of the 143underlying debugging object. 144Argument 145.Ar cu_next_offset 146should point to a location that will be set to the 147offset of the next compilation unit. 148Argument 149.Ar err 150should point to a location that will hold an error descriptor in case 151of an error. 152.Pp 153A value of NULL may be used for any of the arguments 154.Ar cu_length , 155.Ar cu_version , 156.Ar cu_abbrev_offset , 157.Ar cu_pointer_size , 158.Ar cu_offset_size , 159.Ar cu_extension_size , 160.Ar cu_next_offset 161and 162.Ar err 163if the caller is not interested in the respective value. 164.Ss Iterating Through Compilation Units in a Debug Context 165.Pp 166The first call to functions 167.Fn dwarf_next_cu_header_b 168and 169.Fn dwarf_next_cu_header 170for a given debug context will return information about the first 171compilation unit in the debug context. 172Subsequent calls to these functions will iterate through the remaining 173compilation units in the debug context. 174On stepping past the last compilation unit in the debug context, 175functions 176.Fn dwarf_next_cu_header 177and 178.Fn dwarf_next_cu_header_b 179return 180.Dv DW_DLV_NO_ENTRY 181and reset their internal state. 182The next call to these functions will restart from the first compilation 183unit in the debug context. 184.Sh RETURN VALUES 185On success, these functions return 186.Dv DW_DLV_OK . 187In case of an error, they return 188.Dv DW_DLV_ERROR 189and set argument 190.Ar err . 191When there are no more compilation units left to traverse, they return 192.Dv DW_DLV_NO_ENTRY . 193.Sh ERRORS 194These functions can fail with the following error: 195.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT" 196.It Bq Er DW_DLE_ARGUMENT 197Argument 198.Va dbg 199was NULL. 200.El 201.Sh SEE ALSO 202.Xr dwarf 3 , 203.Xr dwarf_get_cu_die_offset_given_cu_header_offset 3 , 204.Xr dwarf_init 3 , 205.Xr dwarf_siblingof 3 206