{"id":222,"date":"2013-04-26T13:29:11","date_gmt":"2013-04-26T05:29:11","guid":{"rendered":"http:\/\/blog.dayandcarrot.net\/?p=222"},"modified":"2013-04-26T13:29:11","modified_gmt":"2013-04-26T05:29:11","slug":"linux%e4%b8%8b%e5%a4%9a%e7%ba%bf%e7%a8%8bpthread%e7%9a%84%e4%bd%bf%e7%94%a8%e4%bb%a5%e5%8f%8a%e4%bf%a1%e5%8f%b7%e9%87%8fsemaphore%e7%9b%b8%e5%85%b3","status":"publish","type":"post","link":"https:\/\/dayandcarrot.space\/?p=222","title":{"rendered":"Linux\u4e0b\u591a\u7ebf\u7a0bpthread\u7684\u4f7f\u7528\u4ee5\u53ca\u4fe1\u53f7\u91cfsemaphore\u76f8\u5173"},"content":{"rendered":"

\u6458\u81ea\uff1a<\/span>http:\/\/www.china-pub.com <\/span><\/span>\u4f5c\u8005<\/span>: <\/span><\/span>\u59da\u7ee7\u950b <\/span>(2001-08-11 09:05:00)
\n<\/span><\/span>\u5173\u952e\u5b57\uff1a<\/span>Linux<\/span><\/span> <\/span><\/span>\u591a\u7ebf\u7a0b<\/span><\/span> <\/span>Pthread<\/span><\/span> semaphore<\/span><\/span><\/span><\/span><\/p>\n

\u7b80\u5355\u7684\u591a\u7ebf\u7a0b\u7f16\u7a0b<\/b><\/span><\/span>
\nLinux<\/span><\/span>\u7cfb\u7edf\u4e0b\u7684\u591a\u7ebf\u7a0b\u9075\u5faa<\/span>POSIX<\/span><\/span>\u7ebf\u7a0b\u63a5\u53e3\uff0c\u79f0\u4e3a<\/span>pthread<\/span><\/span>\u3002\u7f16\u5199<\/span>Linux<\/span><\/span>\u4e0b\u7684\u591a\u7ebf\u7a0b\u7a0b\u5e8f\uff0c\u9700\u8981\u4f7f\u7528\u5934\u6587\u4ef6<\/span>pthread.h<\/span><\/span>\uff0c\u8fde\u63a5\u65f6\u9700\u8981\u4f7f\u7528\u5e93<\/span>libpthread.a<\/span><\/span>\u3002\u987a\u4fbf\u8bf4\u4e00\u4e0b\uff0c<\/span>Linux<\/span><\/span>\u4e0b<\/span>pthread<\/span><\/span>\u7684\u5b9e\u73b0\u662f\u901a\u8fc7\u7cfb\u7edf\u8c03\u7528<\/span>clone<\/span><\/span>\uff08\uff09\u6765\u5b9e\u73b0\u7684\u3002<\/span>clone<\/span><\/span>\uff08\uff09\u662f<\/span>Linux<\/span><\/span>\u6240\u7279\u6709\u7684\u7cfb\u7edf\u8c03\u7528\uff0c\u5b83\u7684\u4f7f\u7528\u65b9\u5f0f\u7c7b\u4f3c<\/span>fork<\/span><\/span>\uff0c\u5173\u4e8e<\/span>clone<\/span><\/span>\uff08\uff09\u7684\u8be6\u7ec6\u60c5\u51b5\uff0c\u6709\u5174\u8da3\u7684\u8bfb\u8005\u53ef\u4ee5\u53bb\u67e5\u770b\u6709\u5173\u6587\u6863\u8bf4\u660e\u3002\u4e0b\u9762\u6211\u4eec\u5c55\u793a\u4e00\u4e2a\u6700\u7b80\u5355\u7684\u591a\u7ebf\u7a0b\u7a0b\u5e8f <\/span>example1.c<\/span><\/span>\u3002<\/span>
\n<pre>
\n\/* example.c*\/
\n#include <stdio.h>
\n#include <pthread.h>
\nvoid thread(void)
\n{
\nint i;
\nfor( i = 0;i < 3; i++ )
\nprintf(“This is a pthread.n”);
\n}
\nint main(void)
\n{
\npthread_t id;
\nint i,ret;
\nret = pthread_create( &id, NULL, (void *)thread, NULL );
\nif ( ret!=0 ) {
\nprintf (“Create pthread error!n”);
\nexit (1);
\n}
\nfor( i = 0; i < 3; i++ )
\nprintf(“This is the main process.n”);
\npthread_join(id,NULL);
\nreturn (0);
\n}
\n<\/pre>
\n\u6211\u4eec\u7f16\u8bd1\u6b64\u7a0b\u5e8f\uff1a<\/span>
\ngcc example1.c -lpthread -o example1
\n<\/span><\/span>\u8fd0\u884c<\/span>example1<\/span><\/span>\uff0c\u6211\u4eec\u5f97\u5230\u5982\u4e0b\u7ed3\u679c\uff1a<\/span>
\nThis is the main process.
\nThis is a pthread.
\nThis is the main process.
\nThis is the main process.
\nThis is a pthread.
\nThis is a pthread.
\n<\/span><\/span>\u518d\u6b21\u8fd0\u884c\uff0c\u6211\u4eec\u53ef\u80fd\u5f97\u5230\u5982\u4e0b\u7ed3\u679c\uff1a<\/span>
\nThis is a pthread.
\nThis is the main process.
\nThis is a pthread.
\nThis is the main process.
\nThis is a pthread.
\nThis is the main process.<\/span><\/span>
\n\u524d\u540e\u4e24\u6b21\u7ed3\u679c\u4e0d\u4e00\u6837\uff0c\u8fd9\u662f\u4e24\u4e2a\u7ebf\u7a0b\u4e89\u593a<\/span>CPU<\/span><\/span>\u8d44\u6e90\u7684\u7ed3\u679c\u3002\u4e0a\u9762\u7684\u793a\u4f8b\u4e2d\uff0c\u6211\u4eec\u4f7f\u7528\u5230\u4e86\u4e24\u4e2a\u51fd\u6570\uff0c\u3000\u3000<\/span>
\npthread_create<\/span><\/span>\u548c<\/span>pthread_join<\/span><\/span>\uff0c\u5e76\u58f0\u660e\u4e86\u4e00\u4e2a<\/span>pthread_t<\/span><\/span>\u578b\u7684\u53d8\u91cf\u3002<\/span>
\npthread_t<\/span><\/span>\u5728\u5934\u6587\u4ef6<\/span>\/usr\/include\/bits\/pthreadtypes.h<\/span><\/span>\u4e2d\u5b9a\u4e49\uff1a<\/span>
\ntypedef unsigned long int pthread_t;
\n<\/span><\/span>\u5b83\u662f\u4e00\u4e2a\u7ebf\u7a0b\u7684\u6807\u8bc6\u7b26\u3002\u51fd\u6570<\/span>pthread_create<\/span><\/span>\u7528\u6765\u521b\u5efa\u4e00\u4e2a\u7ebf\u7a0b\uff0c\u5b83\u7684\u539f\u578b\u4e3a\uff1a<\/span>
\nextern int pthread_create __P ((pthread_t *__thread, __const pthread_attr_t *__attr,
\nvoid *(*__start_routine) (void *), void *__arg));
\n<\/span><\/span>\u7b2c\u4e00\u4e2a\u53c2\u6570\u4e3a\u6307\u5411\u7ebf\u7a0b\u6807\u8bc6\u7b26\u7684\u6307\u9488\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u7528\u6765\u8bbe\u7f6e\u7ebf\u7a0b\u5c5e\u6027\uff0c\u7b2c\u4e09\u4e2a\u53c2\u6570\u662f\u7ebf\u7a0b\u8fd0\u884c\u51fd\u6570\u7684\u8d77\u59cb\u5730\u5740\uff0c\u6700\u540e\u4e00\u4e2a\u53c2\u6570\u662f\u8fd0\u884c\u51fd\u6570\u7684\u53c2\u6570\u3002\u8fd9\u91cc\uff0c\u6211\u4eec\u7684\u51fd\u6570<\/span>thread<\/span><\/span>\u4e0d\u9700\u8981\u53c2\u6570\uff0c\u6240\u4ee5\u6700\u540e\u4e00\u4e2a\u53c2\u6570\u8bbe\u4e3a\u7a7a\u6307\u9488\u3002\u7b2c\u4e8c\u4e2a\u53c2\u6570\u6211\u4eec\u4e5f\u8bbe\u4e3a\u7a7a\u6307\u9488\uff0c\u8fd9\u6837\u5c06\u751f\u6210\u9ed8\u8ba4\u5c5e\u6027\u7684\u7ebf\u7a0b\u3002\u5bf9\u7ebf\u7a0b\u5c5e\u6027\u7684\u8bbe\u5b9a\u548c\u4fee\u6539\u6211\u4eec\u5c06\u5728\u4e0b\u4e00\u8282\u9610\u8ff0\u3002\u5f53\u521b\u5efa\u7ebf\u7a0b\u6210\u529f\u65f6\uff0c\u51fd\u6570\u8fd4\u56de<\/span>0<\/span><\/span>\uff0c\u82e5\u4e0d\u4e3a<\/span>0<\/span><\/span>\u5219\u8bf4\u660e\u521b\u5efa\u7ebf\u7a0b\u5931\u8d25\uff0c\u5e38\u89c1\u7684\u9519\u8bef\u8fd4\u56de\u4ee3\u7801\u4e3a<\/span>EAGAIN<\/span><\/span>\u548c<\/span>EINVAL<\/span><\/span>\u3002\u524d\u8005\u8868\u793a\u7cfb\u7edf\u9650\u5236\u521b\u5efa\u65b0\u7684\u7ebf\u7a0b\uff0c\u4f8b\u5982\u7ebf\u7a0b\u6570\u76ee\u8fc7\u591a\u4e86\uff1b\u540e\u8005\u8868\u793a\u7b2c\u4e8c\u4e2a\u53c2\u6570\u4ee3\u8868\u7684\u7ebf\u7a0b\u5c5e\u6027\u503c\u975e\u6cd5\u3002\u521b\u5efa\u7ebf\u7a0b\u6210\u529f\u540e\uff0c\u65b0\u521b\u5efa\u7684\u7ebf\u7a0b\u5219\u8fd0\u884c\u53c2\u6570\u4e09\u548c\u53c2\u6570\u56db\u786e\u5b9a\u7684\u51fd\u6570\uff0c\u539f\u6765\u7684\u7ebf\u7a0b\u5219\u7ee7\u7eed\u8fd0\u884c\u4e0b\u4e00\u884c\u4ee3\u7801\u3002<\/span>
\n<\/span><\/span>\u51fd\u6570<\/span>pthread_join<\/span><\/span>\u7528\u6765\u7b49\u5f85\u4e00\u4e2a\u7ebf\u7a0b\u7684\u7ed3\u675f\u3002\u51fd\u6570\u539f\u578b\u4e3a\uff1a<\/span>
\nextern int pthread_join __P ((pthread_t __th, void **__thread_return));
\n<\/span><\/span>\u7b2c\u4e00\u4e2a\u53c2\u6570\u4e3a\u88ab\u7b49\u5f85\u7684\u7ebf\u7a0b\u6807\u8bc6\u7b26\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u4e3a\u4e00\u4e2a\u7528\u6237\u5b9a\u4e49\u7684\u6307\u9488\uff0c\u5b83\u53ef\u4ee5\u7528\u6765\u5b58\u50a8\u88ab\u7b49\u5f85\u7ebf\u7a0b\u7684\u8fd4\u56de\u503c\u3002\u8fd9\u4e2a\u51fd\u6570\u662f\u4e00\u4e2a\u7ebf\u7a0b\u963b\u585e\u7684\u51fd\u6570\uff0c\u8c03\u7528\u5b83\u7684\u51fd\u6570\u5c06\u4e00\u76f4\u7b49\u5f85\u5230\u88ab\u7b49\u5f85\u7684\u7ebf\u7a0b\u7ed3\u675f\u4e3a\u6b62\uff0c\u5f53\u51fd\u6570\u8fd4\u56de\u65f6\uff0c\u88ab\u7b49\u5f85\u7ebf\u7a0b\u7684\u8d44\u6e90\u88ab\u6536\u56de\u3002\u4e00\u4e2a\u7ebf\u7a0b\u7684\u7ed3\u675f\u6709\u4e24\u79cd\u9014\u5f84\uff0c\u4e00\u79cd\u662f\u8c61\u6211\u4eec\u4e0a\u9762\u7684\u4f8b\u5b50\u4e00\u6837\uff0c\u51fd\u6570\u7ed3\u675f\u4e86\uff0c\u8c03\u7528\u5b83\u7684\u7ebf\u7a0b\u4e5f\u5c31\u7ed3\u675f\u4e86\uff1b\u53e6\u4e00\u79cd\u65b9\u5f0f\u662f\u901a\u8fc7\u51fd\u6570<\/span>pthread_exit<\/span><\/span>\u6765\u5b9e\u73b0\u3002\u5b83\u7684\u51fd\u6570\u539f\u578b\u4e3a\uff1a<\/span>
\nextern void pthread_exit __P ((void *__retval)) __attribute__ ((__noreturn__));
\n<\/span><\/span>\u552f\u4e00\u7684\u53c2\u6570\u662f\u51fd\u6570\u7684\u8fd4\u56de\u4ee3\u7801\uff0c\u53ea\u8981<\/span>pthread_join<\/span><\/span>\u4e2d\u7684\u7b2c\u4e8c\u4e2a\u53c2\u6570<\/span>thread_return<\/span><\/span>\u4e0d\u662f<\/span>NULL<\/span><\/span>\uff0c\u8fd9\u4e2a\u503c\u5c06\u88ab\u4f20\u9012\u7ed9 <\/span>thread_return<\/span><\/span>\u3002\u6700\u540e\u8981\u8bf4\u660e\u7684\u662f\uff0c\u4e00\u4e2a\u7ebf\u7a0b\u4e0d\u80fd\u88ab\u591a\u4e2a\u7ebf\u7a0b\u7b49\u5f85\uff0c\u5426\u5219\u7b2c\u4e00\u4e2a\u63a5\u6536\u5230\u4fe1\u53f7\u7684\u7ebf\u7a0b\u6210\u529f\u8fd4\u56de\uff0c\u5176\u4f59\u8c03\u7528<\/span>pthread_join<\/span><\/span>\u7684\u7ebf\u7a0b\u5219\u8fd4\u56de\u9519\u8bef\u4ee3\u7801<\/span>ESRCH<\/span><\/span>\u3002<\/span>
\n\u4fe1\u53f7\u91cf<\/b><\/span><\/span>
\n<\/span><\/span>\u4fe1\u53f7\u91cf\u672c\u8d28\u4e0a\u662f\u4e00\u4e2a\u975e\u8d1f\u7684\u6574\u6570\u8ba1\u6570\u5668\uff0c\u5b83\u88ab\u7528\u6765\u63a7\u5236\u5bf9\u516c\u5171\u8d44\u6e90\u7684\u8bbf\u95ee\u3002\u5f53\u516c\u5171\u8d44\u6e90\u589e\u52a0\u65f6\uff0c\u8c03\u7528\u51fd\u6570<\/span>sem_post<\/span><\/span>\uff08\uff09\u589e\u52a0\u4fe1\u53f7\u91cf\u3002\u53ea\u6709\u5f53\u4fe1\u53f7\u91cf\u503c\u5927\u4e8e\uff10\u65f6\uff0c\u624d\u80fd\u4f7f\u7528\u516c\u5171\u8d44\u6e90\uff0c\u4f7f\u7528\u540e\uff0c\u51fd\u6570<\/span>sem_wait<\/span><\/span>\uff08\uff09\u51cf\u5c11\u4fe1\u53f7\u91cf\u3002\u51fd\u6570<\/span>sem_trywait<\/span><\/span>\uff08\uff09\u548c\u51fd\u6570<\/span>pthread_ mutex_trylock<\/span><\/span>\uff08\uff09\u8d77\u540c\u6837\u7684\u4f5c\u7528\uff0c\u5b83\u662f\u51fd\u6570<\/span>sem_wait<\/span><\/span>\uff08\uff09\u7684\u975e\u963b\u585e\u7248\u672c\u3002\u4e0b\u9762\u6211\u4eec\u9010\u4e2a\u4ecb\u7ecd\u548c\u4fe1\u53f7\u91cf\u6709\u5173\u7684\u4e00\u4e9b\u51fd\u6570\uff0c\u5b83\u4eec\u90fd\u5728\u5934\u6587\u4ef6 <\/span>\/usr\/include\/semaphore.h<\/span><\/span>\u4e2d\u5b9a\u4e49\u3002<\/span>
\n<\/span><\/span>\u4fe1\u53f7\u91cf\u7684\u6570\u636e\u7c7b\u578b\u4e3a\u7ed3\u6784<\/span>sem_t<\/span><\/span>\uff0c\u5b83\u672c\u8d28\u4e0a\u662f\u4e00\u4e2a\u957f\u6574\u578b\u7684\u6570\u3002\u51fd\u6570<\/span>sem_init<\/span><\/span>\uff08\uff09\u7528\u6765\u521d\u59cb\u5316\u4e00\u4e2a\u4fe1\u53f7\u91cf\u3002\u5b83\u7684\u539f\u578b\u4e3a\uff1a<\/span>
\nextern int sem_init __P ((sem_t *__sem, int __pshared, unsigned int __value));
\nsem<\/span><\/span>\u4e3a\u6307\u5411\u4fe1\u53f7\u91cf\u7ed3\u6784\u7684\u4e00\u4e2a\u6307\u9488\uff1b<\/span>pshared<\/span><\/span>\u4e0d\u4e3a\uff10\u65f6\u6b64\u4fe1\u53f7\u91cf\u5728\u8fdb\u7a0b\u95f4\u5171\u4eab\uff0c\u5426\u5219\u53ea\u80fd\u4e3a\u5f53\u524d\u8fdb\u7a0b\u7684\u6240\u6709\u7ebf\u7a0b\u5171\u4eab\uff1b<\/span>value<\/span><\/span>\u7ed9\u51fa\u4e86\u4fe1\u53f7\u91cf\u7684\u521d\u59cb\u503c\u3002<\/span>
\n<\/span><\/span>\u51fd\u6570<\/span>sem_post( sem_t *sem )<\/span><\/span>\u7528\u6765\u589e\u52a0\u4fe1\u53f7\u91cf\u7684\u503c\u3002\u5f53\u6709\u7ebf\u7a0b\u963b\u585e\u5728\u8fd9\u4e2a\u4fe1\u53f7\u91cf\u4e0a\u65f6\uff0c\u8c03\u7528\u8fd9\u4e2a\u51fd\u6570\u4f1a\u4f7f\u5176\u4e2d\u7684\u4e00\u4e2a\u7ebf\u7a0b\u4e0d\u5728\u963b\u585e\uff0c\u9009\u62e9\u673a\u5236\u540c\u6837\u662f\u7531\u7ebf\u7a0b\u7684\u8c03\u5ea6\u7b56\u7565\u51b3\u5b9a\u7684\u3002<\/span>
\n<\/span><\/span>\u51fd\u6570<\/span>sem_wait( sem_t *sem )<\/span><\/span>\u88ab\u7528\u6765\u963b\u585e\u5f53\u524d\u7ebf\u7a0b\u76f4\u5230\u4fe1\u53f7\u91cf<\/span>sem<\/span><\/span>\u7684\u503c\u5927\u4e8e<\/span>0<\/span><\/span>\uff0c\u89e3\u9664\u963b\u585e\u540e\u5c06<\/span>sem<\/span><\/span>\u7684\u503c\u51cf\u4e00\uff0c\u8868\u660e\u516c\u5171\u8d44\u6e90\u7ecf\u4f7f\u7528\u540e\u51cf\u5c11\u3002\u51fd\u6570<\/span>sem_trywait ( sem_t *sem )<\/span><\/span>\u662f\u51fd\u6570<\/span>sem_wait<\/span><\/span>\uff08\uff09\u7684\u975e\u963b\u585e\u7248\u672c\uff0c\u5b83\u76f4\u63a5\u5c06\u4fe1\u53f7\u91cf<\/span>sem<\/span><\/span>\u7684\u503c\u51cf\u4e00\u3002<\/span>
\n<\/span><\/span>\u51fd\u6570<\/span>sem_destroy(sem_t *sem)<\/span><\/span>\u7528\u6765\u91ca\u653e\u4fe1\u53f7\u91cf<\/span>sem<\/span><\/span>\u3002<\/span>
\n<\/span><\/span>\u4e0b\u9762\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u4f7f\u7528\u4fe1\u53f7\u91cf\u7684\u4f8b\u5b50\u3002\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u4e00\u5171\u6709<\/span>4<\/span><\/span>\u4e2a\u7ebf\u7a0b\uff0c\u5176\u4e2d\u4e24\u4e2a\u7ebf\u7a0b\u8d1f\u8d23\u4ece\u6587\u4ef6\u8bfb\u53d6\u6570\u636e\u5230\u516c\u5171\u7684\u7f13\u51b2\u533a\uff0c\u53e6\u4e24\u4e2a\u7ebf\u7a0b\u4ece\u7f13\u51b2\u533a\u8bfb\u53d6\u6570\u636e\u4f5c\u4e0d\u540c\u7684\u5904\u7406\uff08\u52a0\u548c\u4e58\u8fd0\u7b97\uff09\u3002<\/span>
\n\/* File sem.c *\/
\n#include <stdio.h>
\n#include <pthread.h>
\n#include <semaphore.h>
\n#define MAXSTACK 100<\/span><\/span>
\nint stack[MAXSTACK][2];
\nint size = 0;
\nsem_t sem;
\n\/* \u4ece\u6587\u4ef6<\/span>1.dat<\/span><\/span>\u8bfb\u53d6\u6570\u636e\uff0c\u6bcf\u8bfb\u4e00\u6b21\uff0c\u4fe1\u53f7\u91cf\u52a0\u4e00<\/span>*\/
\nvoid ReadData1( void )
\n{
\nFILE *fp = fopen( “1.dat”, “r” );<\/span><\/span>
\nwhile ( !feof( fp ) )
\n{
\nfscanf( fp, “%d %d”, &stack[size][0], &stack[size][1] );
\nsem_post( &sem );
\n++size;
\n}
\nfclose(fp);
\n}
\n\/*\u4ece\u6587\u4ef6<\/span>2.dat<\/span><\/span>\u8bfb\u53d6\u6570\u636e<\/span>*\/
\nvoid ReadData2( void )
\n{
\nFILE *fp=fopen(“2.dat”,”r”);<\/span><\/span>
\nwhile ( !feof( fp ) )
\n{
\nfscanf(fp,”%d %d”,&stack[size][0],&stack[size][1]);
\nsem_post(&sem);
\n++size;
\n}
\nfclose(fp);
\n}
\n\/*\u963b\u585e\u7b49\u5f85\u7f13\u51b2\u533a\u6709\u6570\u636e\uff0c\u8bfb\u53d6\u6570\u636e\u540e\uff0c\u91ca\u653e\u7a7a\u95f4\uff0c\u7ee7\u7eed\u7b49\u5f85<\/span>*\/
\nvoid HandleData1( void )
\n{
\nwhile( 1 )
\n{
\nsem_wait( &sem );
\nprintf( “Plus:%d+%d=%dn”, stack[size][0], stack[size][1],
\nstack[size][0]+stack[size][1] );
\n–size;
\n}
\n}<\/span><\/span>
\nvoid HandleData2(void)
\n{
\nwhile ( 1 )
\n{
\nsem_wait( &sem );
\nprintf( “Multiply:%d*%d=%dn”, stack[size][0],stack[size][1],
\nstack[size][0]*stack[size][1] );
\n–size;
\n}
\n}
\nint main(void)
\n{
\npthread_t t1,t2,t3,t4;
\nsem_init( &sem, 0, 0 );
\npthread_create( &t1, NULL, (void *)HandleData1, NULL);
\npthread_create( &t2, NULL, (void *)HandleData2, NULL);
\npthread_create( &t3, NULL, (void *)ReadData1, \u00a0\u00a0\u00a0 NULL);
\npthread_create( &t4, NULL, (void *)ReadData2,\u00a0\u00a0\u00a0 NULL);
\n\/* \u9632\u6b62\u7a0b\u5e8f\u8fc7\u65e9\u9000\u51fa\uff0c\u8ba9\u5b83\u5728\u6b64\u65e0\u9650\u671f\u7b49\u5f85<\/span>*\/
\npthread_join( t1,NULL );
\n}<\/span><\/span>
\n\u5728<\/span>Linux<\/span><\/span>\u4e0b\uff0c\u6211\u4eec\u7528\u547d\u4ee4<\/span>gcc -lpthread sem.c -o sem<\/span><\/span>\u751f\u6210\u53ef\u6267\u884c\u6587\u4ef6<\/span>sem<\/span><\/span>\u3002 \u6211\u4eec\u4e8b\u5148\u7f16\u8f91\u597d\u6570\u636e\u6587\u4ef6<\/span>1.dat<\/span><\/span>\u548c<\/span>2.dat<\/span><\/span>\uff0c\u5047\u8bbe\u5b83\u4eec\u7684\u5185\u5bb9\u5206\u522b\u4e3a<\/span>1 2 3 4 5 6 7 8 9 10<\/span><\/span>\u548c <\/span>-1 -2 -3 -4 -5 -6 -7 -8 -9 -10 <\/span><\/span>\uff0c\u6211\u4eec\u8fd0\u884c<\/span>sem<\/span><\/span>\uff0c\u5f97\u5230\u5982\u4e0b\u7684\u7ed3\u679c\uff1a<\/span>
\nMultiply:-1*-2=2
\nPlus:-1+-2=-3
\nMultiply:9*10=90
\nPlus:-9+-10=-19
\nMultiply:-7*-8=56
\nPlus:-5+-6=-11
\nMultiply:-3*-4=12
\nPlus:9+10=19
\nPlus:7+8=15
\nPlus:5+6=11<\/span><\/span>
\n\u4ece\u4e2d\u6211\u4eec\u53ef\u4ee5\u770b\u51fa\u5404\u4e2a\u7ebf\u7a0b\u95f4\u7684\u7ade\u4e89\u5173\u7cfb\u3002\u800c\u6570\u503c\u5e76\u672a\u6309\u6211\u4eec\u539f\u5148\u7684\u987a\u5e8f\u663e\u793a\u51fa\u6765\u8fd9\u662f\u7531\u4e8e<\/span>size<\/span><\/span>\u8fd9\u4e2a\u6570\u503c\u88ab\u5404\u4e2a\u7ebf\u7a0b\u4efb\u610f\u4fee\u6539\u7684\u7f18\u6545\u3002\u8fd9\u4e5f\u5f80\u5f80\u662f\u591a\u7ebf\u7a0b\u7f16\u7a0b\u8981\u6ce8\u610f\u7684\u95ee\u9898\u3002<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

\u6458\u81ea\uff1ahttp:\/\/www.china-pub.com \u4f5c\u8005: \u59da\u7ee7\u950b (2001-08-11 09:05:00) \u5173\u952e\u5b57\uff1aLinux \u591a\u7ebf\u7a0b Pthread semaphore \u7b80\u5355\u7684\u591a\u7ebf\u7a0b\u7f16\u7a0b Linux\u7cfb\u7edf\u4e0b\u7684\u591a\u7ebf\u7a0b\u9075\u5faaPOSIX\u7ebf\u7a0b\u63a5\u53e3\uff0c\u79f0\u4e3apthread\u3002\u7f16\u5199Linux\u4e0b\u7684\u591a\u7ebf\u7a0b\u7a0b\u5e8f\uff0c\u9700\u8981\u4f7f\u7528\u5934\u6587\u4ef6pthread.h\uff0c\u8fde\u63a5\u65f6\u9700\u8981\u4f7f\u7528\u5e93libpthread.a\u3002\u987a\u4fbf\u8bf4\u4e00\u4e0b\uff0cLinux\u4e0bpthread\u7684\u5b9e\u73b0\u662f\u901a\u8fc7\u7cfb\u7edf\u8c03\u7528clone\uff08\uff09\u6765\u5b9e\u73b0\u7684\u3002clone\uff08\uff09\u662fLinux\u6240\u7279\u6709\u7684\u7cfb\u7edf\u8c03\u7528\uff0c\u5b83\u7684\u4f7f\u7528\u65b9\u5f0f\u7c7b\u4f3cfork\uff0c\u5173\u4e8eclone\uff08\uff09\u7684\u8be6\u7ec6\u60c5\u51b5\uff0c\u6709\u5174\u8da3\u7684\u8bfb\u8005\u53ef\u4ee5\u53bb\u67e5\u770b\u6709\u5173\u6587\u6863\u8bf4\u660e\u3002\u4e0b\u9762\u6211\u4eec\u5c55\u793a\u4e00\u4e2a\u6700\u7b80\u5355\u7684\u591a\u7ebf\u7a0b\u7a0b\u5e8f example1.c\u3002 <pre> \/* example.c*\/ #include <stdio.h> #include <pthread.h> void thread(void) { int i; for( i = 0;i < 3; i++ ) printf(“This is a pthread.n”); } int main(void) { pthread_t id; int i,ret; ret = pthread_create( &id, NULL, (void *)thread, NULL ); if ( […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,8],"tags":[],"class_list":["post-222","post","type-post","status-publish","format-standard","hentry","category-study","category-technical"],"_links":{"self":[{"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/posts\/222","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=222"}],"version-history":[{"count":0,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=\/wp\/v2\/posts\/222\/revisions"}],"wp:attachment":[{"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=222"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=222"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dayandcarrot.space\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=222"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}