1.\" $NetBSD: dwarf_formexprloc.3,v 1.6 2024/03/03 17:37:31 christos Exp $ 2.\" 3.\" Copyright (c) 2010 Joseph Koshy 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_formexprloc.3 3962 2022-03-12 15:56:10Z jkoshy 28.\" 29.Dd July 25, 2010 30.Dt DWARF_FORMEXPRLOC 3 31.Os 32.Sh NAME 33.Nm dwarf_formexprloc 34.Nd return information about a location expression 35.Sh LIBRARY 36.Lb libdwarf 37.Sh SYNOPSIS 38.In libdwarf.h 39.Ft int 40.Fo dwarf_formexprloc 41.Fa "Dwarf_Attribute attr" 42.Fa "Dwarf_Unsigned *retlen" 43.Fa "Dwarf_Ptr *retexpr" 44.Fa "Dwarf_Error *err" 45.Fc 46.Sh DESCRIPTION 47Function 48.Fn dwarf_formexprloc 49allows an application to retrieve the length and the bytes of a 50DWARF location expression. 51.Pp 52Argument 53.Fa attr 54should reference a DWARF attribute of the form 55.Dv DW_FORM_exprloc . 56Argument 57.Fa retlen 58should point to a location that will be set to the length of the 59location expression. 60Argument 61.Fa retexpr 62should point to a location that will be set to a pointer to the 63content of the location expression itself. 64.Pp 65If argument 66.Fa err 67is not 68.Dv NULL , 69it will be used to return an error descriptor in case of an error. 70.Ss Memory Management 71The application should not attempt to free the memory 72area referenced by the pointer returned in argument 73.Fa retexpr . 74.Sh RETURN VALUES 75Function 76.Fn dwarf_formexprloc 77returns 78.Dv DW_DLV_OK 79on success. 80In case of an error, it returns 81.Dv DW_DLV_ERROR 82and sets argument 83.Fa err . 84.Sh ERRORS 85Function 86.Fn dwarf_formexprloc 87may fail with the following errors: 88.Bl -tag -width ".Bq Er DW_DLE_ATTR_FORM_BAD" 89.It Bq Er DW_DLE_ARGUMENT 90One of arguments 91.Fa attr , 92.Fa retlen 93or 94.Fa retexpr 95was 96.Dv NULL . 97.It Bq Er DW_DLE_ATTR_FORM_BAD 98The attribute referenced by argument 99.Fa attr 100was not of form 101.Dv DW_FORM_exprloc . 102.El 103.Sh SEE ALSO 104.Xr dwarf 3 , 105.Xr dwarf_attr 3 , 106.Xr dwarf_formblock 3 , 107.Xr dwarf_formflag 3 , 108.Xr dwarf_formref 3 , 109.Xr dwarf_formsdata 3 , 110.Xr dwarf_formsig8 3 , 111.Xr dwarf_formstring 3 , 112.Xr dwarf_formudata 3 , 113.Xr dwarf_hasattr 3 114