1.\" Copyright (c) 2011 Kai Wang
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25.\" $Id: dwarf_get_str.3 2071 2011-10-27 03:20:00Z jkoshy $
26.\"
27.Dd April 3, 2011
28.Os
29.Dt DWARF_GET_STR 3
30.Sh NAME
31.Nm dwarf_get_str
32.Nd retrieve a string from the DWARF string section
33.Sh LIBRARY
34.Lb libdwarf
35.Sh SYNOPSIS
36.In libdwarf.h
37.Ft int
38.Fo dwarf_get_str
39.Fa "Dwarf_Debug dbg"
40.Fa "Dwarf_Off offset"
41.Fa "char **string"
42.Fa "Dwarf_Signed *len"
43.Fa "Dwarf_Error *err"
44.Fc
45.Sh DESCRIPTION
46Function
47.Fn dwarf_get_str
48retrieves a NUL-terminated string from the DWARF string section
49.Dq ".debug_str" .
50.Pp
51Argument
52.Ar dbg
53should reference a DWARF debug context allocated using
54.Xr dwarf_init 3 .
55.Pp
56Argument
57.Ar offset
58should be an offset, relative to the
59.Dq ".debug_str"
60section, specifying the start of the desired string.
61.Pp
62Argument
63.Ar string
64should point to a location which will hold a returned
65pointer to a NUL-terminated string.
66.Pp
67Argument
68.Ar len
69should point to a location which will hold the length
70of the returned string.
71The returned length does not include the space needed for
72the NUL-terminator.
73.Pp
74If argument
75.Ar err
76is not NULL, it will be used to store error information in case of an
77error.
78.Sh RETURN VALUES
79Function
80.Fn dwarf_get_str
81returns
82.Dv DW_DLV_OK
83when it succeeds.
84It returns
85.Dv DW_DLV_NO_ENTRY
86if there is no
87.Dq ".debug_str"
88section associated with the specified debugging context,
89or if the provided offset
90.Ar offset
91is at the very end of
92.Dq ".debug_str"
93section.
94In case of an error, it returns
95.Dv DW_DLV_ERROR
96and sets the argument
97.Ar err .
98.Sh ERRORS
99Function
100.Fn dwarf_get_str
101can fail with:
102.Bl -tag -width ".Bq Er DW_DLE_NO_ENTRY"
103.It Bq Er DW_DLE_ARGUMENT
104One of the arguments
105.Ar dbg ,
106.Ar string
107or
108.Ar len
109was NULL.
110.It Bq Er DW_DLE_ARGUMENT
111Argument
112.Ar offset
113was out of range.
114.It Bq Er DW_DLE_NO_ENTRY
115The debugging context
116.Ar dbg
117did not contain a
118.Dq ".debug_str"
119string section.
120.It Bq Er DW_DLE_NO_ENTRY
121Argument
122.Ar offset
123was at the very end of the
124.Dq ".debug_str"
125section.
126.El
127.Sh EXAMPLE
128To retrieve all the strings in the DWARF string section, use:
129.Bd -literal -offset indent
130Dwarf_Debug dbg;
131Dwarf_Off offset;
132Dwarf_Signed len;
133Dwarf_Error de;
134char *str;
135int ret
136
137offset = 0;
138while ((ret = dwarf_get_str(dbg, offset, &str, &len, &de)) ==
139	DW_DLV_OK) {
140	/* .. Use the retrieved string. .. */
141	offset += len + 1; /* Account for the terminating NUL. */
142}
143
144if (ret == DW_DLV_ERROR)
145	warnx("dwarf_get_str: %s", dwarf_errmsg(de));
146.Ed
147.Sh SEE ALSO
148.Xr dwarf 3 ,
149.Xr dwarf_init 3
150