1.\"	$NetBSD: dwarf_get_str.3,v 1.2 2014/03/09 16:58:04 christos Exp $
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3.\" Copyright (c) 2011 Kai Wang
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27.\" Id: dwarf_get_str.3 2071 2011-10-27 03:20:00Z jkoshy
28.\"
29.Dd April 3, 2011
30.Os
31.Dt DWARF_GET_STR 3
32.Sh NAME
33.Nm dwarf_get_str
34.Nd retrieve a string from the DWARF string section
35.Sh LIBRARY
36.Lb libdwarf
37.Sh SYNOPSIS
38.In libdwarf.h
39.Ft int
40.Fo dwarf_get_str
41.Fa "Dwarf_Debug dbg"
42.Fa "Dwarf_Off offset"
43.Fa "char **string"
44.Fa "Dwarf_Signed *len"
45.Fa "Dwarf_Error *err"
46.Fc
47.Sh DESCRIPTION
48Function
49.Fn dwarf_get_str
50retrieves a NUL-terminated string from the DWARF string section
51.Dq ".debug_str" .
52.Pp
53Argument
54.Ar dbg
55should reference a DWARF debug context allocated using
56.Xr dwarf_init 3 .
57.Pp
58Argument
59.Ar offset
60should be an offset, relative to the
61.Dq ".debug_str"
62section, specifying the start of the desired string.
63.Pp
64Argument
65.Ar string
66should point to a location which will hold a returned
67pointer to a NUL-terminated string.
68.Pp
69Argument
70.Ar len
71should point to a location which will hold the length
72of the returned string.
73The returned length does not include the space needed for
74the NUL-terminator.
75.Pp
76If argument
77.Ar err
78is not NULL, it will be used to store error information in case of an
79error.
80.Sh RETURN VALUES
81Function
82.Fn dwarf_get_str
83returns
84.Dv DW_DLV_OK
85when it succeeds.
86It returns
87.Dv DW_DLV_NO_ENTRY
88if there is no
89.Dq ".debug_str"
90section associated with the specified debugging context,
91or if the provided offset
92.Ar offset
93is at the very end of
94.Dq ".debug_str"
95section.
96In case of an error, it returns
97.Dv DW_DLV_ERROR
98and sets the argument
99.Ar err .
100.Sh ERRORS
101Function
102.Fn dwarf_get_str
103can fail with:
104.Bl -tag -width ".Bq Er DW_DLE_NO_ENTRY"
105.It Bq Er DW_DLE_ARGUMENT
106One of the arguments
107.Ar dbg ,
108.Ar string
109or
110.Ar len
111was NULL.
112.It Bq Er DW_DLE_ARGUMENT
113Argument
114.Ar offset
115was out of range.
116.It Bq Er DW_DLE_NO_ENTRY
117The debugging context
118.Ar dbg
119did not contain a
120.Dq ".debug_str"
121string section.
122.It Bq Er DW_DLE_NO_ENTRY
123Argument
124.Ar offset
125was at the very end of the
126.Dq ".debug_str"
127section.
128.El
129.Sh EXAMPLE
130To retrieve all the strings in the DWARF string section, use:
131.Bd -literal -offset indent
132Dwarf_Debug dbg;
133Dwarf_Off offset;
134Dwarf_Signed len;
135Dwarf_Error de;
136char *str;
137int ret
138
139offset = 0;
140while ((ret = dwarf_get_str(dbg, offset, &str, &len, &de)) ==
141	DW_DLV_OK) {
142	/* .. Use the retrieved string. .. */
143	offset += len + 1; /* Account for the terminating NUL. */
144}
145
146if (ret == DW_DLV_ERROR)
147	warnx("dwarf_get_str: %s", dwarf_errmsg(de));
148.Ed
149.Sh SEE ALSO
150.Xr dwarf 3 ,
151.Xr dwarf_init 3
152