ae500c1ff8
Highlights: - Make sure that only TLS sections are sorted into TLS segment. - Fixed multiple errors in "Section to Segment mapping". - Man page updates - ar improvements - elfcopy: avoid filter_reloc uninitialized variable for rela - elfcopy: avoid stripping relocations from static binaries - readelf: avoid printing directory in front of absolute path - readelf: add NT_FREEBSD_FEATURE_CTL FreeBSD note type - test improvements NOTES: Some of these changes originated in FreeBSD and simply reduce diffs between contrib and vendor. ELF Tool Chain ar is not (currently) used in FreeBSD, and there are improvements in both FreeBSD and ELF Tool Chain ar that are not in the other. Sponsored by: The FreeBSD Foundation
279 lines
7.3 KiB
Groff
279 lines
7.3 KiB
Groff
.\" Copyright (c) 2010,2014 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_child.3 3644 2018-10-15 19:55:01Z jkoshy $
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.\"
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.Dd December 21, 2014
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.Dt DWARF_CHILD 3
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.Os
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.Sh NAME
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.Nm dwarf_child ,
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.Nm dwarf_offdie ,
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.Nm dwarf_offdie_b ,
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.Nm dwarf_siblingof ,
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.Nm dwarf_siblingof_b
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.Nd retrieve DWARF Debugging Information Entry descriptors
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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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.Fn dwarf_child "Dwarf_Die die" "Dwarf_Die *ret_die" "Dwarf_Error *err"
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.Ft int
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.Fo dwarf_offdie
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.Fa "Dwarf_Debug dbg"
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.Fa "Dwarf_Off offset"
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.Fa "Dwarf_Die *ret_die"
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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_offdie_b
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.Fa "Dwarf_Debug dbg"
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.Fa "Dwarf_Off offset"
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.Fa "Dwarf_Bool is_info"
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.Fa "Dwarf_Die *ret_die"
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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_siblingof
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.Fa "Dwarf_Debug dbg"
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.Fa "Dwarf_Die die"
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.Fa "Dwarf_Die *ret_die"
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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_siblingof_b
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.Fa "Dwarf_Debug dbg"
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.Fa "Dwarf_Die die"
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.Fa "Dwarf_Die *ret_die"
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.Fa "Dwarf_Bool is_info"
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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 are used to retrieve and traverse DWARF
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Debugging Information Entry (DIE) descriptors associated with
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a compilation unit.
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These descriptors are arranged in the form of a tree, traversable
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using
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.Dq child
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and
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.Dq sibling
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links; see
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.Xr dwarf 3
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for more information.
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DWARF Debugging Information Entry descriptors are represented
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by the
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.Vt Dwarf_Die
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opaque type.
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.Pp
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Function
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.Fn dwarf_child
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retrieves the child of descriptor denoted by argument
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.Ar die ,
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and stores it in the location pointed to by argument
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.Ar ret_die .
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.Pp
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Function
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.Fn dwarf_siblingof
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retrieves the sibling of the descriptor denoted by argument
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.Ar die ,
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and stores it in the location pointed to by argument
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.Ar ret_die .
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If argument
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.Ar die
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is NULL, the first debugging information entry descriptor for the
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current compilation unit will be returned.
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This function and function
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.Fn dwarf_child
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may be used together to traverse the tree of debugging information
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entry descriptors for a compilation unit.
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.Pp
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Function
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.Fn dwarf_siblingof_b
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is identical to the function
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.Fn dwarf_siblingof
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except that it can retrieve the sibling descriptor from either the
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current compilation unit or type unit.
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If argument
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.Ar is_info
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is non-zero, the function behaves identically to function
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.Fn dwarf_siblingof .
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If argument
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.Ar is_info
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is zero, the descriptor referred by argument
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.Ar die
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should be associated with a debugging information entry in the
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type unit.
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The function will store the sibling of the descriptor in the location
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pointed to by argument
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.Ar ret_die .
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If argument
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.Ar is_info
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is zero and argument
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.Ar die
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is
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.Dv NULL ,
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the first debugging information entry descriptor for the
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current type unit will be returned.
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.Pp
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Function
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.Fn dwarf_offdie
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retrieves the debugging information entry descriptor at global offset
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.Ar offset
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in the
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.Dq .debug_info
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section of the object associated with argument
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.Ar dbg .
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The returned descriptor is written to the location pointed to by argument
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.Ar ret_die .
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.Pp
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Function
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.Fn dwarf_offdie_b
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is identical to the function
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.Fn dwarf_offdie
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except that it can retrieve the debugging information entry descriptor at
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global offset
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.Ar offset
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from either of the
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.Dq .debug_info
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and
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.Dq .debug_types
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sections of the object associated with argument
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.Ar dbg .
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If argument
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.Ar is_info
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is non-zero, the function will retrieve the debugging information
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entry from the
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.Dq .debug_info
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section, otherwise the function will retrieve the debugging
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information entry from the
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.Dq .debug_types
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section.
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The returned descriptor is written to the location pointed to by argument
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.Ar ret_die .
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.Ss Memory Management
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The memory area used for the
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.Vt Dwarf_Die
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descriptor returned in argument
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.Ar ret_die
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is allocated by the
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.Lb libdwarf .
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Application code should use function
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.Fn dwarf_dealloc
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with the allocation type
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.Dv DW_DLA_DIE
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to free the memory area when the
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.Vt Dwarf_Die
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descriptor is no longer needed.
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.Sh RETURN VALUES
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These functions return the following values:
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.Bl -tag -width ".Bq Er DW_DLV_NO_ENTRY"
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.It Bq Er DW_DLV_OK
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The call succeeded.
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.It Bq Er DW_DLV_ERROR
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The requested operation failed.
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Additional information about the error encountered will be recorded in
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argument
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.Ar err ,
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if it is not NULL.
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.It Bq Er DW_DLV_NO_ENTRY
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For functions
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.Fn dwarf_child ,
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.Fn dwarf_siblingof
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and
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.Fn dwarf_siblingof_b ,
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the descriptor denoted by argument
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.Ar die
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did not have a child or sibling.
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.Pp
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For functions
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.Fn dwarf_offdie
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and
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.Fn dwarf_offdie_b ,
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there was no debugging information entry at the offset specified by
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argument
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.Ar offset .
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.El
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.Sh EXAMPLES
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To retrieve the first DWARF Debugging Information Entry descriptor for
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the first compilation unit associated with a
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.Vt Dwarf_Debug
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instance, and to traverse all its children, use:
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.Bd -literal -offset indent
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Dwarf_Debug dbg;
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Dwarf_Die die, die0;
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Dwarf_Error de;
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\&... allocate dbg using dwarf_init() etc ...
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if (dwarf_next_cu_header(dbg, NULL, NULL, NULL, NULL, NULL, &de) !=
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DW_DLV_OK)
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errx(EXIT_FAILURE, "dwarf_next_cu_header: %s",
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dwarf_errmsg(de));
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/* Get the first DIE for the current compilation unit. */
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die = NULL;
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if (dwarf_siblingof(dbg, die, &die0, &de) != DW_DLV_OK)
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errx(EXIT_FAILURE, "dwarf_siblingof: %s", dwarf_errmsg(de));
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/* Get the first child of this DIE. */
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die = die0;
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if (dwarf_child(die, &die0, &de) != DW_DLV_OK)
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errx(EXIT_FAILURE, "dwarf_child: %s", dwarf_errmsg(de));
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/* Get the rest of children. */
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do {
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die = die0;
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if (dwarf_siblingof(dbg, die, &die0, &de) == DW_DLV_ERROR)
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errx(EXIT_FAILURE, "dwarf_siblingof: %s",
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dwarf_errmsg(de));
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} while (die0 != NULL);
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.Ed
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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_DIE_NO_CU_CONTEXT"
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.It Bq Er DW_DLE_ARGUMENT
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Arguments
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.Ar dbg ,
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.Ar die
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or
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.Ar ret_die
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were NULL.
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.It Bq Er DW_DLE_DIE_NO_CU_CONTEXT
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Argument
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.Ar dbg
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was not associated with a compilation unit.
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.It Bq Er DW_DLE_NO_ENTRY
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The descriptor denoted by argument
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.Ar die
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had no child or sibling, or there was no DWARF debugging information
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entry at the offset specified by argument
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.Va offset .
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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_errmsg 3 ,
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.Xr dwarf_get_die_infotypes_flag 3 ,
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.Xr dwarf_next_cu_header 3
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