120 lines
3.3 KiB
Groff
120 lines
3.3 KiB
Groff
.\" Copyright (c) 2010 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_attr.3 2072 2011-10-27 03:26:49Z jkoshy $
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.\"
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.Dd April 8, 2010
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.Os
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.Dt DWARF_ATTR 3
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.Sh NAME
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.Nm dwarf_attr
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.Nd retrieve an attribute descriptor associated with 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_attr
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.Fa "Dwarf_Die die"
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.Fa "Dwarf_Half attr"
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.Fa "Dwarf_Attribute *atp"
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.Fa "Dwarf_Error *err"
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.Fc
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.Sh DESCRIPTION
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Function
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.Fn dwarf_attr
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retrieves the attribute descriptor for an attribute associated
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with the DWARF debugging information entry descriptor in
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argument
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.Ar die .
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.Pp
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DWARF attribute descriptors are represented by value of the opaque
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type
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.Vt Dwarf_Attribute ,
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see
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.Xr dwarf 3 .
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.Pp
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Argument
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.Ar attr
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names the desired DWARF attribute.
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Legal values for argument
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.Ar attr
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are those denoted by the
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.Dv DW_AT_*
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constants in the DWARF specification.
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.Pp
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Argument
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.Ar atp
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points to a location into which the returned attribute descriptor
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will be written.
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The returned descriptor may then be passed to the form query functions in the
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.Xr dwarf 3
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API set to access the data associated with the attribute.
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.Pp
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If argument
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.Ar err
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is non-NULL, it will be used to return an error descriptor in case
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of an error.
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.Sh RETURN VALUES
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Function
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.Fn dwarf_attr
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returns
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.Dv DW_DLV_OK on success.
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.Pp
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If the debugging information entry descriptor denoted by argument
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.Ar die
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does not contain the named attribute, the function returns
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.Dv DW_DLV_NO_ENTRY
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and sets argument
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.Ar err .
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For other errors, it returns
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.Dv DW_DLV_ERROR
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and sets argument
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.Ar err .
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.Sh ERRORS
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Function
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.Fn dwarf_attr
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can fail with the following errors:
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.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
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.It Bq Er DW_DLE_ARGUMENT
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Either of arguments
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.Ar die
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or
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.Ar atp
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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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had no attribute corresponding to the value
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in argument
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.Ar attr .
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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_attrlist 3 ,
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.Xr dwarf_hasattr 3 ,
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.Xr dwarf_hasform 3 ,
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.Xr dwarf_whatattr 3 ,
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.Xr dwarf_whatform 3
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