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25.\" $Id: dwarf_attrlist.3 3644 2018-10-15 19:55:01Z jkoshy $
26.\"
27.Dd November 9, 2011
28.Dt DWARF_ATTRLIST 3
29.Os
30.Sh NAME
31.Nm dwarf_attrlist
32.Nd retrieve DWARF attribute descriptors
33.Sh LIBRARY
34.Lb libdwarf
35.Sh SYNOPSIS
36.In libdwarf.h
37.Ft int
38.Fo dwarf_attrlist
39.Fa "Dwarf_Die die"
40.Fa "Dwarf_Attribute **attrbuf"
41.Fa "Dwarf_Signed *attrcount"
42.Fa "Dwarf_Error *err"
43.Fc
44.Sh DESCRIPTION
45Function
46.Fn dwarf_attrlist
47retrieves the DWARF attribute descriptors associated with a
48debugging information entry descriptor in argument
49.Ar die .
50The descriptors are returned as an array of values of the opaque type
51.Vt Dwarf_Attribute .
52The data associated with each returned attribute descriptor may be
53queried using the form query functions in the
54.Xr dwarf 3
55API set.
56.Pp
57Argument
58.Ar attrbuf
59points to a location that will hold a pointer to the returned
60array of DWARF attribute descriptors.
61Argument
62.Ar attrcount
63points to a location that will hold the number of descriptors in
64the returned array.
65.Pp
66If argument
67.Ar err
68is non-NULL, it is used to return an error descriptor in case of an
69error.
70.Ss Memory Management
71In the current implementation, the memory allocated for each DWARF
72attribute descriptor and for the returned array of descriptors is
73managed by the library and the application does not need to explicitly
74free the returned pointers.
75However, for compatibility with other implementations of the
76.Xr dwarf 3
77API, the application is permitted to pass the pointers returned by to
78the
79.Fn dwarf_dealloc
80function.
81.Sh RETURN VALUES
82Function
83.Fn dwarf_attrlist
84returns
85.Dv DW_DLV_OK
86on success.
87.Pp
88If the debugging information entry descriptor denoted by argument
89.Ar die
90does not contain any attribute, the function returns
91.Dv DW_DLV_NO_ENTRY
92and sets argument
93.Ar err .
94For other errors, it returns
95.Dv DW_DLV_ERROR
96and sets argument
97.Ar err .
98.Sh EXAMPLES
99To retrieve the attribute list for a DWARF debugging information
100entry use:
101.Bd -literal -offset indent
102Dwarf_Die dw_die;
103Dwarf_Error dw_e;
104Dwarf_Unsigned dw_count;
105Dwarf_Attribute *dw_attributes;
106int error, i;
107
108\&... variable dw_die contains a reference to the DIE of interest ...
109
110/* Retrieve the attribute list from the DIE. */
111if ((error = dwarf_attrlist(dw_die, &dw_attributes, &dw_count,
112	&dw_e)) != DW_DLV_OK)
113	errx(EXIT_FAILURE, "dwarf_attrlist: %s", dwarf_errmsg(dw_e));
114
115/* Process the attribute list. */
116for (i = 0; i < dw_count; ++i) {
117	/* Use the returned pointers in dw_attributes[i] here. */
118}
119.Ed
120.Sh ERRORS
121Function
122.Fn dwarf_diename
123can fail with the following errors:
124.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
125.It Bq Er DW_DLE_ARGUMENT
126Arguments
127.Ar die ,
128.Ar attrbuf ,
129or
130.Ar attrcount
131were NULL.
132.It Bq Er DW_DLE_NO_ENTRY
133Argument
134.Ar die
135had no attributes.
136.It Bq Er DW_DLE_MEMORY
137An out of memory condition was encountered during the execution of the
138function.
139.El
140.Sh SEE ALSO
141.Xr dwarf 3 ,
142.Xr dwarf_attr 3 ,
143.Xr dwarf_dealloc 3 ,
144.Xr dwarf_hasattr 3 ,
145.Xr dwarf_hasform 3 ,
146.Xr dwarf_whatattr 3 ,
147.Xr dwarf_whatform 3
148