\uc774\ub984\uc788\ub294 \uc138\ub9c8\ud3ec\uc5b4 \ub9d0\uace0 \uba54\ubaa8\ub9ac\uc5d0 \uc62c\ub824 \uc0ac\uc6a9\ud558\ub294 \ubc29\ubc95\ub3c4 \uc788\ub2e4. \ucc45\uc740 sem_init(…, \ub450\ubc88\uc9f8 arg,…)\uc5d0\uc11c \ub450\ubc88\uc9f8 \uc785\ub825\ud558\ub294 \uc22b\uc790\ub97c thread\uc5d0\uc11c \uacf5\uc720\ud560 \uac70\uba74 0, \ud504\ub85c\uc138\uc2a4\uac04 \ud560\uac70\uba74 1\ub85c \ud558\ub77c\uace0 \ud55c\ub2e4. 1\ub85c \ud558\uc5ec thread\ub3c4 \uc798 \ub41c\ub2e4.<\/p>\n\n\n\n
named semaphore\ub294 \ud3ec\uc778\ud130\ub97c \uc120\uc5b8\ud588\uace0 \ud30c\uc77c\uc5d0 \uc601\uc5ed\uc744 \ub9cc\ub4e4\uc5c8\ub2e4. \uc774\uc640 \ub2e4\ub974\uac8c \uc9c1\uc811 \ub370\uc774\ud130\ub97c \uc120\uc5b8\ud558\uace0 \uc8fc\uc18c\ub85c \ub118\uaca8\uc918\uc57c \ud55c\ub2e4.<\/p>\n\n\n\n
ipcs\ub85c \ubcf4\uc77c \ubc95 \ud55c\ub370, \uc548 \ubcf4\uc778\ub2e4. \ubb34\uc5c7\uc774 \uc798\ubabb\ub418\uc5c8\ub294\uc9c0 \ubaa8\ub974\uaca0\ub2e4.<\/p>\n\n\n\n
\/* include main *\/\n#include <pthread.h>\n#include <stdio.h>\n#include <stdlib.h>\n#include <fcntl.h>\n#include <semaphore.h>\n#include <sys\/stat.h>\n#include <unistd.h>\n#define\tNBUFF\t 10\n#define\tSEM_MUTEX\t\"mutex\"\t \t\/* these are args to px_ipc_name() *\/\n#define\tSEM_NEMPTY\t\"empty\"\n#define\tSEM_NSTORED\t\"nstored\"\n\nint\t\tnitems;\t\t\t\t\t\/* read-only by producer and consumer *\/\nstruct {\t\/* data shared by producer and consumer *\/\n int\tbuff[NBUFF];\n \/\/\ud3ec\uc778\ud130 \ub300\uc2e0 \uc138\ub9c8\ud3ec\uc5b4\ub85c \ubcc0\uacbd.\n \/\/sem_t\t*mutex, *nempty, *nstored;\n sem_t\tmutex, nempty, nstored;\t\t\/* semaphores, not pointers *\/\n\n} shared;\n\nvoid\t*produce(void *), *consume(void *);\n\nint\nmain(int argc, char **argv)\n{\n\tpthread_t\ttid_produce, tid_consume;\n\n\tif (argc != 2)\n\t\tperror(\"usage: prodcons1 <#items>\");\n\tnitems = atoi(argv[1]);\n\t\t\/* 4create three semaphores *\/\n\t\/\/memory based\ub85c \ubcc0\uacbd.\n\t\/*\n\tshared.mutex = sem_open(SEM_MUTEX, O_CREAT | O_EXCL,\n\t\t\t\t\t\t\t0660, 1);\n\tshared.nempty = sem_open(SEM_NEMPTY, O_CREAT | O_EXCL,\n\t\t\t\t\t\t\t 0660, NBUFF);\n\tshared.nstored = sem_open(SEM_NSTORED, O_CREAT | O_EXCL,\n\t\t\t\t\t\t\t 0660, 0);\n\t\t\t\t\t\t\t *\/\n\n\n\t\/\/\ub450\ubc88\uc9f8 \ud30c\ub77c\ubbf8\ud130\ub97c 0\uc73c\ub85c \uc124\uc815\ud574\uc57c thread\uac04 \uc804\ub2ec.\n\t\/\/sem_init(&shared.mutex, 1, 1) \uc124\uc815\ud574\ub3c4 \uc798 \ub428..\n\n\tsem_init(&shared.mutex, 0, 1);\n\tsem_init(&shared.nempty, 0, NBUFF);\n\tsem_init(&shared.nstored, 0, 0);\n\n\n\t\t\/* 4create one producer thread and one consumer thread *\/\n\t\/\/pthread_setconcurrency(2);\n\t\/\/pthread_setconcurrency();\n\tpthread_create(&tid_produce, NULL, produce, NULL);\n\tpthread_create(&tid_consume, NULL, consume, NULL);\n\n\t\t\/* 4wait for the two threads *\/\n\tpthread_join(tid_produce, NULL);\n\tpthread_join(tid_consume, NULL);\n\n\t\t\/* 4remove the semaphores *\/\n\t\/\/\uba54\ubaa8\ub9ac \ubca0\uc774\uc2a4\ub85c \ubcc0\uacbd.\n\t\/*\n\tsem_unlink(SEM_MUTEX);\n\tsem_unlink(SEM_NEMPTY);\n\tsem_unlink(SEM_NSTORED);\n\t*\/\n\n\n\t\/\/ipcs\ub85c \ud655\uc778\ud558\uae30\uc704\ud574 \ub300\uae30\n\tsleep(10);\n\n\tsem_destroy(&shared.mutex);\n\tsem_destroy(&shared.nempty);\n\tsem_destroy(&shared.nstored);\n\n\texit(0);\n}\n\/* end main *\/\n\n\/* include prodcons *\/\nvoid *\nproduce(void *arg)\n{\n\tint\t\ti;\n\n\tfor (i = 0; i < nitems; i++) {\n\n\t\tsem_wait(&shared.nempty);\t\/* wait for at least 1 empty slot *\/\n\t\tsem_wait(&shared.mutex);\n\n\t\tshared.buff[i % NBUFF] = i;\t\/* store i into circular buffer *\/\n\t\tsem_post(&shared.mutex);\n\t\tsem_post(&shared.nstored);\t\/* 1 more stored item *\/\n\n\n\t}\n\treturn(NULL);\n}\n\nvoid *\nconsume(void *arg)\n{\n\tint\t\ti;\n\tint tmpnempty, tmpmutex, tmpnstored;\n\n\tfor (i = 0; i < nitems; i++) {\n\n\n\t\tsem_wait(&shared.nstored);\t\t\/* wait for at least 1 stored item *\/\n\t\tsem_wait(&shared.mutex);\n\n\n\t\tif (shared.buff[i % NBUFF] = i)\n\t\t\tprintf(\"buff[%d] = %d\\n\", i, shared.buff[i % NBUFF]);\n\t\tsem_post(&shared.mutex);\n\t\tsem_post(&shared.nempty);\t\t\/* 1 more empty slot *\/\n\n\t}\n\treturn(NULL);\n}\n\/* end prodcons *\/\n<\/pre>\n\n\n\npi@raspberrypi:~\/Project\/cCode\/IPC $ ipcs\n\n------ Message Queues --------\nkey msqid owner perms used-bytes messages \n\n------ Shared Memory Segments --------\nkey shmid owner perms bytes nattch status \n\n------ Semaphore Arrays --------\nkey semid owner perms nsems \n\n<\/pre>\n\n\n\nipcs\ub294 system V \uae30\ub2a5\uc774\ub77c posix semaphore\ub294 \ud574\ub2f9\ud558\uc9c0 \uc54a\ub294\ub2e4. \ubcf4\uc774\uc9c0 \uc54a\uc74c\uc774 \ub2f9\uc5f0\ud558\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"
\uc774\ub984\uc788\ub294 \uc138\ub9c8\ud3ec\uc5b4 \ub9d0\uace0 \uba54\ubaa8\ub9ac\uc5d0 \uc62c\ub824 \uc0ac\uc6a9\ud558\ub294 \ubc29\ubc95\ub3c4 \uc788\ub2e4. \ucc45\uc740 sem_init(…, \ub450\ubc88\uc9f8 arg,…)\uc5d0\uc11c \ub450\ubc88\uc9f8 \uc785\ub825\ud558\ub294 \uc22b\uc790\ub97c thread\uc5d0\uc11c \uacf5\uc720\ud560 \uac70\uba74 0, \ud504\ub85c\uc138\uc2a4\uac04 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[12],"tags":[775,53,781,784,786],"class_list":["post-3858","post","type-post","status-publish","format-standard","hentry","category-12","tag-c","tag-linux","tag-network-program","tag-pthread","tag-semaphore"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/posts\/3858","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/comments?post=3858"}],"version-history":[{"count":3,"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/posts\/3858\/revisions"}],"predecessor-version":[{"id":3877,"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/posts\/3858\/revisions\/3877"}],"wp:attachment":[{"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/media?parent=3858"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/categories?post=3858"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/now0930.pe.kr\/wordpress\/wp-json\/wp\/v2\/tags?post=3858"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}