1.\"	$NetBSD: dwarf_add_AT_location_expr.3,v 1.2 2014/03/09 16:58:03 christos Exp $
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3.\" Copyright (c) 2011 Kai Wang
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27.\" Id: dwarf_add_AT_location_expr.3 2072 2011-10-27 03:26:49Z jkoshy
28.\"
29.Dd September 5, 2011
30.Os
31.Dt DWARF_ADD_AT_LOCATION_EXPR 3
32.Sh NAME
33.Nm dwarf_add_AT_location_expr
34.Nd create an attribute descriptor for a location expression
35.Sh LIBRARY
36.Lb libdwarf
37.Sh SYNOPSIS
38.In libdwarf.h
39.Ft "Dwarf_P_Attribute"
40.Fo dwarf_add_AT_location_expr
41.Fa "Dwarf_P_Debug dbg"
42.Fa "Dwarf_P_Die die"
43.Fa "Dwarf_Half attr"
44.Fa "Dwarf_P_Expr loc_expr"
45.Fa "Dwarf_Error *err"
46.Fc
47.Sh DESCRIPTION
48Function
49.Fn dwarf_add_AT_location_expr
50creates an attribute descriptor for a location expression and attaches
51it to the debugging information entry referenced by argument
52.Ar die .
53.Pp
54Argument
55.Ar dbg
56should reference a DWARF producer instance allocated using
57.Xr dwarf_producer_init 3
58or
59.Xr dwarf_producer_init_b 3 .
60.Pp
61Argument
62.Ar die
63should reference a debugging information entry allocated using
64.Xr dwarf_new_die 3 .
65.Pp
66Argument
67.Ar attr
68specifies the attribute code of the created attribute descriptor.
69.Pp
70Argument
71.Ar loc_expr
72should reference a location expression descriptor allocated using
73.Xr dwarf_new_expr 3 .
74.Pp
75The attribute created by function
76.Fn dwarf_add_AT_location_expr
77will have one of the DWARF forms
78.Dv DW_FORM_block ,
79.Dv DW_FORM_block1 ,
80.Dv DW_FORM_block2
81or
82.Dv DW_FORM_block4 ,
83depending on the size of the byte stream generated by the location
84expression descriptor referenced by argument
85.Ar loc_expr .
86.Pp
87If argument
88.Ar err
89is not NULL, it will be used by to store error information in case of
90an error.
91.Sh RETURN VALUES
92On success, function
93.Fn dwarf_add_AT_location_expr
94returns the created attribute descriptor.
95In case of an error, function
96.Fn dwarf_add_AT_location_expr
97returns
98.Dv DW_DLV_BADADDR
99and sets the argument
100.Ar err .
101.Sh ERRORS
102Function
103.Fn dwarf_add_AT_location_expr
104can fail with:
105.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
106.It Bq Er DW_DLE_ARGUMENT
107One of the arguments
108.Ar dbg ,
109.Ar die
110or
111.Ar loc_expr
112was NULL.
113.It Bq Er DW_DLE_MEMORY
114An out of memory condition was encountered during the execution of the
115function.
116.El
117.Sh SEE ALSO
118.Xr dwarf 3 ,
119.Xr dwarf_new_die 3 ,
120.Xr dwarf_new_expr 3 ,
121.Xr dwarf_producer_init 3 ,
122.Xr dwarf_producer_init_b 3
123