9_posix_msgqueue.tgz

#include <stdio.h> #include <string.h> #include <fcntl.h> /* For O_* constants */ #include <sys/stat.h> /* For mode constants */ #include <mqueue.h> #include <errno.h> #include <stdlib.h> #include "slnmq.h" int sln_ipc_mq_loop(void) { mqd_t mqd; struct mq_attr setattr, attr; char *recvbuf = NULL; unsigned int prio; int recvlen; memset(&setattr, 0, sizeof(setattr)); setattr.mq_maxmsg = SLN_IPC_MQ_MAXMSG; setattr.mq_msgsize = SLN_IPC_MQ_MSGSIZE; mqd = mq_open(SLN_IPC_MQ_NAME, O_RDWR | O_CREAT | O_EXCL, 0644, &setattr); //mqd = mq_open(SLN_IPC_MQ_NAME, O_RDWR | O_CREAT | O_EXCL, 0644, NULL); if ((mqd < 0) && (errno != EEXIST)) { fprintf(stderr, "mq_open: %s\n", strerror(errno)); return -1; } if ((mqd < 0) && (errno == EEXIST)) { // name is exist mqd = mq_open(SLN_IPC_MQ_NAME, O_RDWR); if (mqd < 0) { fprintf(stderr, "mq_open: %s\n", strerror(errno)); return -1; } } if (mq_getattr(mqd, &attr) < 0) { fprintf(stderr, "mq_getattr: %s\n", strerror(errno)); return -1; } printf("flags: %ld, maxmsg: %ld, msgsize: %ld, curmsgs: %ld\n", attr.mq_flags, attr.mq_maxmsg, attr.mq_msgsize, attr.mq_curmsgs); recvbuf = malloc(attr.mq_msgsize); if (NULL == recvbuf) { return -1; } sleep(10); for (;;) { if (mq_getattr(mqd, &attr) < 0) { fprintf(stderr, "mq_getattr: %s\n", strerror(errno)); return -1; } printf("msgsize: %ld, curmsgs: %ld\n", attr.mq_msgsize, attr.mq_curmsgs); recvlen = mq_receive(mqd, recvbuf, attr.mq_msgsize, &prio); if (recvlen < 0) { fprintf(stderr, "mq_receive: %s\n", strerror(errno)); continue; } printf("recvive-> prio: %d, recvbuf: %s\n", prio, recvbuf); sleep(1); } mq_close(mqd); return 0; } int main(int argc, const char *argv[]) { if (sln_ipc_mq_loop() < 0) { return -1; } return 0; }