~mdw / mLib / blame
| 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 |