Mercurial > sdl-ios-xcode
annotate src/thread/generic/SDL_sysmutex.c @ 1361:19418e4422cb
New configure-based build system. Still work in progress, but much improved
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Thu, 16 Feb 2006 10:11:48 +0000 |
| parents | c71e05b4dc2e |
| children | d910939febfa |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
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Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
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3 Copyright (C) 1997-2006 Sam Lantinga |
| 0 | 4 |
| 5 This library is free software; you can redistribute it and/or | |
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Sam Lantinga <slouken@libsdl.org>
parents:
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diff
changeset
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6 modify it under the terms of the GNU Lesser General Public |
| 0 | 7 License as published by the Free Software Foundation; either |
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c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
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8 version 2.1 of the License, or (at your option) any later version. |
| 0 | 9 |
| 10 This library is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
|
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Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
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diff
changeset
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13 Lesser General Public License for more details. |
| 0 | 14 |
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1312
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
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15 You should have received a copy of the GNU Lesser General Public |
|
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
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16 License along with this library; if not, write to the Free Software |
|
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
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17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 0 | 18 |
| 19 Sam Lantinga | |
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Sam Lantinga <slouken@libsdl.org>
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20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 /* An implementation of mutexes using semaphores */ | |
| 24 | |
| 25 #include "SDL_thread.h" | |
| 26 #include "SDL_systhread_c.h" | |
| 27 | |
| 28 | |
| 29 struct SDL_mutex { | |
| 30 int recursive; | |
| 31 Uint32 owner; | |
| 32 SDL_sem *sem; | |
| 33 }; | |
| 34 | |
| 35 /* Create a mutex */ | |
| 36 SDL_mutex *SDL_CreateMutex(void) | |
| 37 { | |
| 38 SDL_mutex *mutex; | |
| 39 | |
| 40 /* Allocate mutex memory */ | |
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parents:
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diff
changeset
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41 mutex = (SDL_mutex *)SDL_malloc(sizeof(*mutex)); |
| 0 | 42 if ( mutex ) { |
| 43 /* Create the mutex semaphore, with initial value 1 */ | |
| 44 mutex->sem = SDL_CreateSemaphore(1); | |
| 45 mutex->recursive = 0; | |
| 46 mutex->owner = 0; | |
| 47 if ( ! mutex->sem ) { | |
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3692456e7b0f
Use SDL_ prefixed versions of C library functions.
Sam Lantinga <slouken@libsdl.org>
parents:
1330
diff
changeset
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48 SDL_free(mutex); |
| 0 | 49 mutex = NULL; |
| 50 } | |
| 51 } else { | |
| 52 SDL_OutOfMemory(); | |
| 53 } | |
| 54 return mutex; | |
| 55 } | |
| 56 | |
| 57 /* Free the mutex */ | |
| 58 void SDL_DestroyMutex(SDL_mutex *mutex) | |
| 59 { | |
| 60 if ( mutex ) { | |
| 61 if ( mutex->sem ) { | |
| 62 SDL_DestroySemaphore(mutex->sem); | |
| 63 } | |
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3692456e7b0f
Use SDL_ prefixed versions of C library functions.
Sam Lantinga <slouken@libsdl.org>
parents:
1330
diff
changeset
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64 SDL_free(mutex); |
| 0 | 65 } |
| 66 } | |
| 67 | |
| 68 /* Lock the semaphore */ | |
| 69 int SDL_mutexP(SDL_mutex *mutex) | |
| 70 { | |
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New configure-based build system. Still work in progress, but much improved
Sam Lantinga <slouken@libsdl.org>
parents:
1358
diff
changeset
|
71 #if SDL_THREADS_DISABLED |
| 0 | 72 return 0; |
| 73 #else | |
| 74 Uint32 this_thread; | |
| 75 | |
| 76 if ( mutex == NULL ) { | |
| 77 SDL_SetError("Passed a NULL mutex"); | |
| 78 return -1; | |
| 79 } | |
| 80 | |
| 81 this_thread = SDL_ThreadID(); | |
| 82 if ( mutex->owner == this_thread ) { | |
| 83 ++mutex->recursive; | |
| 84 } else { | |
| 85 /* The order of operations is important. | |
| 86 We set the locking thread id after we obtain the lock | |
| 87 so unlocks from other threads will fail. | |
| 88 */ | |
| 89 SDL_SemWait(mutex->sem); | |
| 90 mutex->owner = this_thread; | |
| 91 mutex->recursive = 0; | |
| 92 } | |
| 93 | |
| 94 return 0; | |
|
1361
19418e4422cb
New configure-based build system. Still work in progress, but much improved
Sam Lantinga <slouken@libsdl.org>
parents:
1358
diff
changeset
|
95 #endif /* SDL_THREADS_DISABLED */ |
| 0 | 96 } |
| 97 | |
| 98 /* Unlock the mutex */ | |
| 99 int SDL_mutexV(SDL_mutex *mutex) | |
| 100 { | |
|
1361
19418e4422cb
New configure-based build system. Still work in progress, but much improved
Sam Lantinga <slouken@libsdl.org>
parents:
1358
diff
changeset
|
101 #if SDL_THREADS_DISABLED |
| 0 | 102 return 0; |
| 103 #else | |
| 104 if ( mutex == NULL ) { | |
| 105 SDL_SetError("Passed a NULL mutex"); | |
| 106 return -1; | |
| 107 } | |
| 108 | |
| 109 /* If we don't own the mutex, we can't unlock it */ | |
| 110 if ( SDL_ThreadID() != mutex->owner ) { | |
| 111 SDL_SetError("mutex not owned by this thread"); | |
| 112 return -1; | |
| 113 } | |
| 114 | |
| 115 if ( mutex->recursive ) { | |
| 116 --mutex->recursive; | |
| 117 } else { | |
| 118 /* The order of operations is important. | |
| 119 First reset the owner so another thread doesn't lock | |
| 120 the mutex and set the ownership before we reset it, | |
| 121 then release the lock semaphore. | |
| 122 */ | |
| 123 mutex->owner = 0; | |
| 124 SDL_SemPost(mutex->sem); | |
| 125 } | |
| 126 return 0; | |
|
1361
19418e4422cb
New configure-based build system. Still work in progress, but much improved
Sam Lantinga <slouken@libsdl.org>
parents:
1358
diff
changeset
|
127 #endif /* SDL_THREADS_DISABLED */ |
| 0 | 128 } |