Commit | Line | Data |
---|---|---|
b317b99d MW |
1 | /* -*-c-*- |
2 | * | |
3 | * Duplicate multiple files | |
4 | * | |
5 | * (c) 2008 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with this program; if not, write to the Free Software Foundation, | |
22 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
23 | */ | |
24 | ||
25 | #ifndef MDUP_H | |
26 | #define MDUP_H | |
27 | ||
28 | #ifdef __cplusplus | |
29 | extern "C" { | |
30 | #endif | |
31 | ||
32 | /*----- Data structures ---------------------------------------------------*/ | |
33 | ||
34 | typedef struct mdup_fd { | |
35 | int cur; /* Current file descriptor */ | |
36 | int want; /* File descriptor wanted */ | |
37 | } mdup_fd; | |
38 | ||
39 | /*----- Functions provided ------------------------------------------------*/ | |
40 | ||
41 | /* --- @mdup@ --- * | |
42 | * | |
43 | * Arguments: @mdup_fd *v@ = pointer to @mdup_fd@ vector | |
44 | * @size_t n@ = size of vector | |
45 | * | |
46 | * Returns: Zero if successful, @-1@ on failure. | |
47 | * | |
48 | * Use: Rearranges file descriptors. | |
49 | * | |
b317b99d MW |
50 | * The vector @v@ consists of a number of @mdup_fd@ structures. |
51 | * Each `slot' in the table represents a file. The slot's @cur@ | |
52 | * member names the current file descriptor for this file; the | |
53 | * @want@ member is the file descriptor we want to use for it. | |
54 | * if you want to keep a file alive but don't care which | |
55 | * descriptor it ends up with, set @want = -1@. Several slots | |
56 | * may specify the same @cur@ descriptor; but they all have to | |
57 | * declare different @want@s (except that several slots may have | |
58 | * @want = -1@. | |
59 | * | |
60 | * On successful exit, the function will have rearranged the | |
61 | * file descriptors as requested. To reflect this, the @cur@ | |
62 | * members will all be set to match the (non-@-1@) @want@ | |
63 | * members. | |
64 | * | |
65 | * If there is a failure, then some rearrangement may have been | |
66 | * performed and some not; the @cur@ members are set to reflect | |
67 | * which file descriptors are to be used. The old file | |
68 | * descriptors are closed. (This is different from usual @dup@ | |
69 | * behaviour, of course, but essential for reliable error | |
70 | * handling.) If you want to keep a particular source file | |
71 | * descriptor open as well as make a new copy then specify two | |
72 | * slots with the same @cur@, one with @want = cur@ and one with | |
73 | * the desired output descriptor. | |
74 | * | |
75 | * This function works correctly even if the desired remappings | |
76 | * contain cycles. | |
77 | */ | |
78 | ||
79 | extern int mdup(mdup_fd */*v*/, size_t /*n*/); | |
80 | ||
81 | /*----- That's all, folks -------------------------------------------------*/ | |
82 | ||
83 | #ifdef __cplusplus | |
84 | } | |
85 | #endif | |
86 | ||
87 | #endif |