ffb40783fd
Highlights of changes between r3490 and r3520: - Improve C++ demangling - Improve compatibility with Binutils tools wrt. error messages - Handle additional types/sections/etc. in readelf and elfdump - addr2line, cxxfilt: use setvbuf to set line buffering for filter use PR: 218395 MFC after: 2 weeks Relnotes: Yes Sponsored by: The FreeBSD Foundation
226 lines
5.8 KiB
Groff
226 lines
5.8 KiB
Groff
.\" Copyright (c) 2011 Kai Wang
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $Id: dwarf_attrval_signed.3 3509 2016-12-29 03:58:41Z emaste $
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.\"
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.Dd December 26, 2016
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.Os
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.Dt DWARF_ATTRVAL_SIGNED 3
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.Sh NAME
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.Nm dwarf_attrval_flag ,
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.Nm dwarf_attrval_signed ,
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.Nm dwarf_attrval_string ,
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.Nm dwarf_attrval_unsigned
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.Nd retrieve the value of an attribute within a DWARF debugging information entry
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.Sh LIBRARY
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.Lb libdwarf
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.Sh SYNOPSIS
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.In libdwarf.h
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.Ft int
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.Fo dwarf_attrval_flag
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.Fa "Dwarf_Die die"
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.Fa "Dwarf_Half attr"
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.Fa "Dwarf_Bool *ret"
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.Fa "Dwarf_Error *err"
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.Fc
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.Ft int
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.Fo dwarf_attrval_signed
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.Fa "Dwarf_Die die"
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.Fa "Dwarf_Half attr"
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.Fa "Dwarf_Signed *ret"
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.Fa "Dwarf_Error *err"
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.Fc
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.Ft int
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.Fo dwarf_attrval_string
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.Fa "Dwarf_Die die"
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.Fa "Dwarf_Half attr"
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.Fa "const char **ret"
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.Fa "Dwarf_Error *err"
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.Fc
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.Ft int
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.Fo dwarf_attrval_unsigned
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.Fa "Dwarf_Die die"
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.Fa "Dwarf_Half attr"
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.Fa "Dwarf_Unsigned *ret"
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.Fa "Dwarf_Error *err"
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.Fc
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.Sh DESCRIPTION
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These functions search the debugging information entry referenced
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by argument
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.Ar die
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for the attribute named by argument
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.Ar attr .
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If the named attribute is found, the functions set the location
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pointed to by argument
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.Ar ret
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to the value of the attribute.
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The argument
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.Ar err ,
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if non NULL,
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will be used to return an error descriptor in case of an error.
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.Pp
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Function
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.Fn dwarf_attrval_flag
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sets the location pointed to by argument
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.Ar ret
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to either 0 or 1. If the form of the attribute named by argument
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.Ar attr
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is
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.Dv DW_FORM_flag ,
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function
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.Fn dwarf_attrval_flag
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sets the location pointed to by argument
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.Ar ret
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to 1 if the attribute has a non-zero value, or to 0 otherwise.
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If the form of the attribute named by argument
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.Ar attr
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is
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.Dv DW_FORM_flag_present ,
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function
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.Fn dwarf_attrval_flag
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unconditionally sets the location pointed to by argument
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.Ar ret
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to 1.
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The form of the attribute must be one of
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.Dv DW_FORM_flag
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or
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.Dv DW_FORM_flag_present .
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.Pp
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Function
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.Fn dwarf_attrval_signed
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stores the value for the attribute named by argument
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.Ar attr ,
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into the location pointed to by argument
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.Ar ret .
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The attribute's value is treated as a signed integral quantity and is
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sign-extended as needed.
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The attribute named by the argument
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.Ar attr
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must belong to the
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.Dv CONSTANT
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class and must have one of the following forms:
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.Dv DW_FORM_data1 ,
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.Dv DW_FORM_data2 ,
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.Dv DW_FORM_data4 ,
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.Dv DW_FORM_data8
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or
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.Dv DW_FORM_sdata .
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.Pp
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Function
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.Fn dwarf_attrval_string
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sets the location pointed to by argument
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.Ar ret
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to a pointer to a NUL-terminated string that is the value of the
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attribute named by argument
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.Ar attr .
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The form of the attribute must be one of
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.Dv DW_FORM_string
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or
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.Dv DW_FORM_strp .
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.Pp
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Function
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.Fn dwarf_attrval_unsigned
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stores the value for the attribute named by argument
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.Ar attr
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into the location pointed to by argument
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.Ar ret .
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The attribute's value is treated as an unsigned integral quantity, and
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is zero-extended as needed.
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The named attribute must belong to one of the
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.Dv CONSTANT ,
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.Dv ADDRESS
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or
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.Dv REFERENCE
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classes and must have one of the following forms:
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.Dv DW_FORM_addr ,
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.Dv DW_FORM_data1 ,
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.Dv DW_FORM_data2 ,
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.Dv DW_FORM_data4 ,
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.Dv DW_FORM_data8 ,
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.Dv DW_FORM_udata ,
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.Dv DW_FORM_ref1 ,
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.Dv DW_FORM_ref2 ,
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.Dv DW_FORM_ref4 ,
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.Dv DW_FORM_ref8 ,
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or
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.Dv DW_FORM_ref_udata .
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.Pp
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If the attribute named by argument
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.Ar attr
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is
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.Dv DW_AT_type
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and is not present in the debugging information entry referenced by argument
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.Ar die ,
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and if a
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.Dv DW_AT_abstract_origin
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or
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.Dv DW_AT_specification
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attribute is present in the debugging information entry,
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function
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.Fn dwarf_attrval_unsigned
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will search for the named attribute in the debugging information entry
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referenced by the
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.Dv DW_AT_abstract_origin
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or
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.Dv DW_AT_specification
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attribute.
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.Sh RETURN VALUES
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On success, these functions returns
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.Dv DW_DLV_OK .
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If the named attribute was not found in the specified debugging
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information entry descriptor these functions return
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.Dv DW_DLV_NO_ENTRY
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and set argument
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.Ar err .
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For other errors, these functions return
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.Dv DW_DLV_ERROR
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and set argument
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.Ar err .
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.Sh COMPATIBILITY
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These functions are extensions added by this implementation of the
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DWARF(3) API.
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.Sh ERRORS
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These functions may fail with the following errors:
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.Bl -tag -width ".Bq Er DW_DLE_ATTR_FORM_BAD"
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.It Bq Er DW_DLE_ARGUMENT
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Either of the arguments
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.Va die
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or
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.Va ret
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was NULL.
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.It Bq Er DW_DLE_NO_ENTRY
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Argument
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.Ar die
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did not contain an attribute corresponding to the value in argument
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.Ar attr .
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.It Bq Er DW_DLE_ATTR_FORM_BAD
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The attribute named by argument
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.Ar attr
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was not of a permitted form.
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.El
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.Sh SEE ALSO
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.Xr dwarf 3 ,
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.Xr dwarf_attr 3 ,
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.Xr dwarf_hasattr 3
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