1.\" Copyright (c) 2011 Kai Wang
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25.\" $Id: dwarf_undef_macro.3 2122 2011-11-09 15:35:14Z jkoshy $
26.\"
27.Dd November 9, 2011
28.Os
29.Dt DWARF_UNDEF_MACRO 3
30.Sh NAME
31.Nm dwarf_undef_macro
32.Nd record the removal of a macro definition
33.Sh LIBRARY
34.Lb libdwarf
35.Sh SYNOPSIS
36.In libdwarf.h
37.Ft "int"
38.Fo dwarf_undef_macro
39.Fa "Dwarf_P_Debug dbg"
40.Fa "Dwarf_Unsigned lineno"
41.Fa "char *name"
42.Fa "Dwarf_Error *err"
43.Fc
44.Sh DESCRIPTION
45Function
46.Fn dwarf_undef_macro
47records the removal of a macro definition in a DWARF producer
48instance.
49.Pp
50Argument
51.Ar dbg
52should reference a DWARF producer instance allocated using
53.Xr dwarf_producer_init 3
54or
55.Xr dwarf_producer_init_b 3 .
56.Pp
57Argument
58.Ar lineno
59specifies the line number of the source line where the macro
60definition was removed.
61A value of zero indicates that the macro definition was removed before
62any source files were read.
63.Pp
64Argument
65.Ar name
66should point to a NUL-terminated string containing the name
67of the macro.
68.Pp
69If argument
70.Ar err
71is not NULL, it will be used to store error information in case of an
72error.
73.Sh RETURN VALUES
74On success, function
75.Fn dwarf_undef_macro
76returns
77.Dv DW_DLV_OK .
78In case of an error, function
79.Fn dwarf_undef_macro
80returns
81.Dv DW_DLV_ERROR
82and sets the argument
83.Ar err .
84.Sh EXAMPLE
85To record the fact that the macro named
86.Dv _STDIO_H_
87was removed at line 220 of the current macro file, use:
88.Bd -literal -offset indent
89Dwarf_P_Debug dbg;
90Dwarf_Error de;
91
92/* ... Assume 'dbg' refers to a DWARF producer instance... */
93if (dwarf_undef_macro(dbg, 220, "_STDIO_H_", &de) != DW_DLV_OK)
94	errx(EXIT_FAILURE, "dwarf_def_macro failed: %s",
95	    dwarf_errmsg(-1));
96.Ed
97.Sh ERRORS
98Function
99.Fn dwarf_undef_macro
100can fail with:
101.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
102.It Bq Er DW_DLE_ARGUMENT
103Either arguments
104.Ar dbg
105or
106.Ar name
107was NULL.
108.It Bq Er DW_DLE_MEMORY
109An out of memory condition was encountered during the execution of the
110function.
111.El
112.Sh SEE ALSO
113.Xr dwarf 3 ,
114.Xr dwarf_def_macro 3 ,
115.Xr dwarf_end_macro_file 3 ,
116.Xr dwarf_producer_init 3 ,
117.Xr dwarf_producer_init_b 3 ,
118.Xr dwarf_start_macro_file 3 ,
119.Xr dwarf_vendor_ext 3
120