1 | .\" Copyright (c) 2006,2008 Joseph Koshy. All rights reserved. |
---|
2 | .\" |
---|
3 | .\" Redistribution and use in source and binary forms, with or without |
---|
4 | .\" modification, are permitted provided that the following conditions |
---|
5 | .\" are met: |
---|
6 | .\" 1. Redistributions of source code must retain the above copyright |
---|
7 | .\" notice, this list of conditions and the following disclaimer. |
---|
8 | .\" 2. Redistributions in binary form must reproduce the above copyright |
---|
9 | .\" notice, this list of conditions and the following disclaimer in the |
---|
10 | .\" documentation and/or other materials provided with the distribution. |
---|
11 | .\" |
---|
12 | .\" This software is provided by Joseph Koshy ``as is'' and |
---|
13 | .\" any express or implied warranties, including, but not limited to, the |
---|
14 | .\" implied warranties of merchantability and fitness for a particular purpose |
---|
15 | .\" are disclaimed. in no event shall Joseph Koshy be liable |
---|
16 | .\" for any direct, indirect, incidental, special, exemplary, or consequential |
---|
17 | .\" damages (including, but not limited to, procurement of substitute goods |
---|
18 | .\" or services; loss of use, data, or profits; or business interruption) |
---|
19 | .\" however caused and on any theory of liability, whether in contract, strict |
---|
20 | .\" liability, or tort (including negligence or otherwise) arising in any way |
---|
21 | .\" out of the use of this software, even if advised of the possibility of |
---|
22 | .\" such damage. |
---|
23 | .\" |
---|
24 | .\" $Id$ |
---|
25 | .\" |
---|
26 | .Dd June 11, 2006 |
---|
27 | .Os |
---|
28 | .Dt ELF_ERRMSG 3 |
---|
29 | .Sh NAME |
---|
30 | .Nm elf_errmsg , |
---|
31 | .Nm elf_errno |
---|
32 | .Nd ELF library error message handling |
---|
33 | .Sh LIBRARY |
---|
34 | .Lb libelf |
---|
35 | .Sh SYNOPSIS |
---|
36 | .In libelf.h |
---|
37 | .Ft int |
---|
38 | .Fn elf_errno "void" |
---|
39 | .Ft "const char *" |
---|
40 | .Fn elf_errmsg "int error" |
---|
41 | .Sh DESCRIPTION |
---|
42 | When an error occurs during an ELF library API call, the library |
---|
43 | encodes the error using an error number and stores the error number |
---|
44 | internally for retrieval by the application at a later point of time. |
---|
45 | Error numbers may contain an OS supplied error code in addition to |
---|
46 | an ELF API specific error code. |
---|
47 | An error number value of zero indicates no error. |
---|
48 | .Pp |
---|
49 | Function |
---|
50 | .Fn elf_errno |
---|
51 | is used to retrieve the last error recorded by the ELF library. |
---|
52 | Invoking this function has the side-effect of resetting the |
---|
53 | ELF library's recorded error number to zero. |
---|
54 | .Pp |
---|
55 | The function |
---|
56 | .Fn elf_errmsg |
---|
57 | returns a null-terminated string with a human readable |
---|
58 | description of the error specified in argument |
---|
59 | .Ar error . |
---|
60 | A zero value for argument |
---|
61 | .Ar error |
---|
62 | retrieves the most recent error encountered by the ELF |
---|
63 | library. |
---|
64 | An argument value of -1 behaves identically, except that |
---|
65 | it guarantees a non-NULL return from |
---|
66 | .Fn elf_errmsg . |
---|
67 | .Sh RETURN VALUES |
---|
68 | Function |
---|
69 | .Fn elf_errno |
---|
70 | returns a non-zero value encoding the last error encountered |
---|
71 | by the ELF library, or zero if no error was encountered. |
---|
72 | .Pp |
---|
73 | Function |
---|
74 | .Fn elf_errmsg |
---|
75 | returns a pointer to library local storage for non-zero values |
---|
76 | of argument |
---|
77 | .Ar error . |
---|
78 | With a zero argument, the function will return a NULL pointer if no |
---|
79 | error had been encountered by the library, or will return a pointer to |
---|
80 | library local storage containing an appropriate message otherwise. |
---|
81 | .Sh EXAMPLES |
---|
82 | Clearing the ELF library's recorded error number can be accomplished |
---|
83 | by invoking |
---|
84 | .Fn elf_errno |
---|
85 | and discarding its return value. |
---|
86 | .Bd -literal -offset indent |
---|
87 | /* clear error */ |
---|
88 | (void) elf_errno(); |
---|
89 | .Ed |
---|
90 | .Pp |
---|
91 | Retrieving a human-readable description of the current error number |
---|
92 | can be done with the following snippet: |
---|
93 | .Bd -literal -offset indent |
---|
94 | int err; |
---|
95 | const char *errmsg; |
---|
96 | \&... |
---|
97 | err = elf_errno(); |
---|
98 | if (err != 0) |
---|
99 | errmsg = elf_errmsg(err); |
---|
100 | .Ed |
---|
101 | .Sh SEE ALSO |
---|
102 | .Xr elf 3 , |
---|
103 | .Xr gelf 3 |
---|
104 | .Sh BUGS |
---|
105 | Function |
---|
106 | .Fn elf_errmsg |
---|
107 | is not localized. |
---|