~mdw / mLib / blame
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|---|---|---|
| b317b99d MW |
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. | |
| b317b99d MW |
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 | * | |
| b317b99d MW |
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 |