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1 | /* -*-c-*- |
2 | * | |
3 | * Duplicate multiple files | |
4 | * | |
5 | * (c) 2008 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
5744f36c | 10 | * This file is part of the mLib utilities library. |
b317b99d | 11 | * |
5744f36c MW |
12 | * mLib is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of the | |
15 | * License, or (at your option) any later version. | |
16 | * | |
17 | * mLib is distributed in the hope that it will be useful, | |
b317b99d MW |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
5744f36c | 20 | * GNU Library General Public License for more details. |
b317b99d | 21 | * |
5744f36c MW |
22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with mLib; if not, write to the Free | |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
25 | * MA 02111-1307, USA. | |
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26 | */ |
27 | ||
28 | #ifndef MDUP_H | |
29 | #define MDUP_H | |
30 | ||
31 | #ifdef __cplusplus | |
32 | extern "C" { | |
33 | #endif | |
34 | ||
35 | /*----- Data structures ---------------------------------------------------*/ | |
36 | ||
37 | typedef struct mdup_fd { | |
38 | int cur; /* Current file descriptor */ | |
39 | int want; /* File descriptor wanted */ | |
40 | } mdup_fd; | |
41 | ||
42 | /*----- Functions provided ------------------------------------------------*/ | |
43 | ||
44 | /* --- @mdup@ --- * | |
45 | * | |
46 | * Arguments: @mdup_fd *v@ = pointer to @mdup_fd@ vector | |
47 | * @size_t n@ = size of vector | |
48 | * | |
49 | * Returns: Zero if successful, @-1@ on failure. | |
50 | * | |
51 | * Use: Rearranges file descriptors. | |
52 | * | |
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53 | * The vector @v@ consists of a number of @mdup_fd@ structures. |
54 | * Each `slot' in the table represents a file. The slot's @cur@ | |
55 | * member names the current file descriptor for this file; the | |
56 | * @want@ member is the file descriptor we want to use for it. | |
57 | * if you want to keep a file alive but don't care which | |
58 | * descriptor it ends up with, set @want = -1@. Several slots | |
59 | * may specify the same @cur@ descriptor; but they all have to | |
60 | * declare different @want@s (except that several slots may have | |
61 | * @want = -1@. | |
62 | * | |
63 | * On successful exit, the function will have rearranged the | |
64 | * file descriptors as requested. To reflect this, the @cur@ | |
65 | * members will all be set to match the (non-@-1@) @want@ | |
66 | * members. | |
67 | * | |
68 | * If there is a failure, then some rearrangement may have been | |
69 | * performed and some not; the @cur@ members are set to reflect | |
70 | * which file descriptors are to be used. The old file | |
71 | * descriptors are closed. (This is different from usual @dup@ | |
72 | * behaviour, of course, but essential for reliable error | |
73 | * handling.) If you want to keep a particular source file | |
74 | * descriptor open as well as make a new copy then specify two | |
75 | * slots with the same @cur@, one with @want = cur@ and one with | |
76 | * the desired output descriptor. | |
77 | * | |
78 | * This function works correctly even if the desired remappings | |
79 | * contain cycles. | |
80 | */ | |
81 | ||
82 | extern int mdup(mdup_fd */*v*/, size_t /*n*/); | |
83 | ||
84 | /*----- That's all, folks -------------------------------------------------*/ | |
85 | ||
86 | #ifdef __cplusplus | |
87 | } | |
88 | #endif | |
89 | ||
90 | #endif |