1.\" $NetBSD: dwarf_attr.3,v 1.2 2014/03/09 16:58:03 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_attr.3 2072 2011-10-27 03:26:49Z jkoshy 28.\" 29.Dd April 8, 2010 30.Os 31.Dt DWARF_ATTR 3 32.Sh NAME 33.Nm dwarf_attr 34.Nd retrieve an attribute descriptor associated with a DWARF debugging information entry 35.Sh LIBRARY 36.Lb libdwarf 37.Sh SYNOPSIS 38.In libdwarf.h 39.Ft int 40.Fo dwarf_attr 41.Fa "Dwarf_Die die" 42.Fa "Dwarf_Half attr" 43.Fa "Dwarf_Attribute *atp" 44.Fa "Dwarf_Error *err" 45.Fc 46.Sh DESCRIPTION 47Function 48.Fn dwarf_attr 49retrieves the attribute descriptor for an attribute associated 50with the DWARF debugging information entry descriptor in 51argument 52.Ar die . 53.Pp 54DWARF attribute descriptors are represented by value of the opaque 55type 56.Vt Dwarf_Attribute , 57see 58.Xr dwarf 3 . 59.Pp 60Argument 61.Ar attr 62names the desired DWARF attribute. 63Legal values for argument 64.Ar attr 65are those denoted by the 66.Dv DW_AT_* 67constants in the DWARF specification. 68.Pp 69Argument 70.Ar atp 71points to a location into which the returned attribute descriptor 72will be written. 73The returned descriptor may then be passed to the form query functions in the 74.Xr dwarf 3 75API set to access the data associated with the attribute. 76.Pp 77If argument 78.Ar err 79is non-NULL, it will be used to return an error descriptor in case 80of an error. 81.Sh RETURN VALUES 82Function 83.Fn dwarf_attr 84returns 85.Dv DW_DLV_OK on success. 86.Pp 87If the debugging information entry descriptor denoted by argument 88.Ar die 89does not contain the named attribute, the function returns 90.Dv DW_DLV_NO_ENTRY 91and sets argument 92.Ar err . 93For other errors, it returns 94.Dv DW_DLV_ERROR 95and sets argument 96.Ar err . 97.Sh ERRORS 98Function 99.Fn dwarf_attr 100can fail with the following errors: 101.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT" 102.It Bq Er DW_DLE_ARGUMENT 103Either of arguments 104.Ar die 105or 106.Ar atp 107was NULL. 108.It Bq Er DW_DLE_NO_ENTRY 109Argument 110.Ar die 111had no attribute corresponding to the value 112in argument 113.Ar attr . 114.El 115.Sh SEE ALSO 116.Xr dwarf 3 , 117.Xr dwarf_attrlist 3 , 118.Xr dwarf_hasattr 3 , 119.Xr dwarf_hasform 3 , 120.Xr dwarf_whatattr 3 , 121.Xr dwarf_whatform 3 122