| 1 | .\" Copyright (c) 2010 Kai Wang |
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| 2 | .\" All rights reserved. |
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| 3 | .\" |
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| 4 | .\" Redistribution and use in source and binary forms, with or without |
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| 5 | .\" modification, are permitted provided that the following conditions |
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| 6 | .\" are met: |
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| 7 | .\" 1. Redistributions of source code must retain the above copyright |
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| 8 | .\" notice, this list of conditions and the following disclaimer. |
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| 9 | .\" 2. Redistributions in binary form must reproduce the above copyright |
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| 10 | .\" notice, this list of conditions and the following disclaimer in the |
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| 11 | .\" documentation and/or other materials provided with the distribution. |
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| 12 | .\" |
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| 13 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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| 14 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 15 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 16 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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| 17 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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| 19 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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| 23 | .\" SUCH DAMAGE. |
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| 25 | .\" $Id: dwarf_attr.3 3093 2014-09-02 22:09:40Z kaiwang27 $ |
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| 26 | .\" |
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| 27 | .Dd April 8, 2010 |
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| 28 | .Os |
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| 29 | .Dt DWARF_ATTR 3 |
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| 30 | .Sh NAME |
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| 31 | .Nm dwarf_attr |
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| 32 | .Nd retrieve an attribute descriptor associated with a DWARF debugging information entry |
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| 33 | .Sh LIBRARY |
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| 34 | .Lb libdwarf |
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| 35 | .Sh SYNOPSIS |
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| 36 | .In libdwarf.h |
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| 37 | .Ft int |
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| 38 | .Fo dwarf_attr |
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| 39 | .Fa "Dwarf_Die die" |
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| 40 | .Fa "Dwarf_Half attr" |
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| 41 | .Fa "Dwarf_Attribute *atp" |
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| 42 | .Fa "Dwarf_Error *err" |
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| 43 | .Fc |
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| 44 | .Sh DESCRIPTION |
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| 45 | Function |
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| 46 | .Fn dwarf_attr |
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| 47 | retrieves the attribute descriptor for an attribute associated |
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| 48 | with the DWARF debugging information entry descriptor in |
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| 49 | argument |
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| 50 | .Ar die . |
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| 51 | .Pp |
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| 52 | DWARF attribute descriptors are represented by value of the opaque |
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| 53 | type |
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| 54 | .Vt Dwarf_Attribute , |
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| 55 | see |
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| 56 | .Xr dwarf 3 . |
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| 57 | .Pp |
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| 58 | Argument |
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| 59 | .Ar attr |
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| 60 | names the desired DWARF attribute. |
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| 61 | Legal values for argument |
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| 62 | .Ar attr |
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| 63 | are those denoted by the |
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| 64 | .Dv DW_AT_* |
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| 65 | constants in the DWARF specification. |
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| 66 | .Pp |
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| 67 | Argument |
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| 68 | .Ar atp |
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| 69 | points to a location into which the returned attribute descriptor |
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| 70 | will be written. |
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| 71 | The returned descriptor may then be passed to the form query functions in the |
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| 72 | .Xr dwarf 3 |
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| 73 | API set to access the data associated with the attribute. |
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| 74 | .Pp |
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| 75 | If argument |
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| 76 | .Ar err |
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| 77 | is non-NULL, it will be used to return an error descriptor in case |
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| 78 | of an error. |
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| 79 | .Sh RETURN VALUES |
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| 80 | Function |
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| 81 | .Fn dwarf_attr |
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| 82 | returns |
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| 83 | .Dv DW_DLV_OK on success. |
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| 84 | .Pp |
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| 85 | If the debugging information entry descriptor denoted by argument |
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| 86 | .Ar die |
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| 87 | does not contain the named attribute, the function returns |
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| 88 | .Dv DW_DLV_NO_ENTRY |
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| 89 | and sets argument |
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| 90 | .Ar err . |
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| 91 | For other errors, it returns |
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| 92 | .Dv DW_DLV_ERROR |
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| 93 | and sets argument |
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| 94 | .Ar err . |
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| 95 | .Sh ERRORS |
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| 96 | Function |
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| 97 | .Fn dwarf_attr |
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| 98 | can fail with the following errors: |
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| 99 | .Bl -tag -width ".Bq Er DW_DLE_ARGUMENT" |
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| 100 | .It Bq Er DW_DLE_ARGUMENT |
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| 101 | Either of arguments |
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| 102 | .Ar die |
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| 103 | or |
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| 104 | .Ar atp |
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| 105 | was NULL. |
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| 106 | .It Bq Er DW_DLE_NO_ENTRY |
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| 107 | Argument |
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| 108 | .Ar die |
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| 109 | had no attribute corresponding to the value |
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| 110 | in argument |
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| 111 | .Ar attr . |
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| 112 | .El |
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| 113 | .Sh SEE ALSO |
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| 114 | .Xr dwarf 3 , |
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| 115 | .Xr dwarf_attrlist 3 , |
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| 116 | .Xr dwarf_attroffset 3 , |
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| 117 | .Xr dwarf_hasattr 3 , |
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| 118 | .Xr dwarf_hasform 3 , |
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| 119 | .Xr dwarf_whatattr 3 , |
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| 120 | .Xr dwarf_whatform 3 |
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