1.\" $NetBSD: dwarf_attr.3,v 1.4 2020/11/26 22:51:35 jkoshy 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 3644 2018-10-15 19:55:01Z jkoshy 28.\" 29.Dd April 8, 2010 30.Dt DWARF_ATTR 3 31.Os 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 86on success. 87.Pp 88If the debugging information entry descriptor denoted by argument 89.Ar die 90does not contain the named attribute, the function returns 91.Dv DW_DLV_NO_ENTRY 92and sets argument 93.Ar err . 94For other errors, it returns 95.Dv DW_DLV_ERROR 96and sets argument 97.Ar err . 98.Sh ERRORS 99Function 100.Fn dwarf_attr 101can fail with the following errors: 102.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT" 103.It Bq Er DW_DLE_ARGUMENT 104Either of arguments 105.Ar die 106or 107.Ar atp 108was NULL. 109.It Bq Er DW_DLE_NO_ENTRY 110Argument 111.Ar die 112had no attribute corresponding to the value 113in argument 114.Ar attr . 115.El 116.Sh SEE ALSO 117.Xr dwarf 3 , 118.Xr dwarf_attrlist 3 , 119.Xr dwarf_attroffset 3 , 120.Xr dwarf_hasattr 3 , 121.Xr dwarf_hasform 3 , 122.Xr dwarf_whatattr 3 , 123.Xr dwarf_whatform 3 124