l3.libnazgul/src/queueInit.c

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2004-02-23 21:30:30 +00:00
#include "libnazgul.h"
#include "ids.h"
msgQueue * queueInit(msgSpaceId externId, int queueIdx) {
int queueFd;
msgQueue * queue;
sem_t * semaphore;
msgQueueId queueId;
queue = NULL;
if(msgQueueIdIntern(queueId, externId, queueIdx) < 0) {
return NULL;
}
queueFd = shm_open(queueId, O_RDWR|O_CREAT|O_EXCL|O_TRUNC, MSGSPACE_DEFAULT_MODE);
if(queueFd == -1) {
fprintf(stderr, "queueInit : %s initialisation failed: %s\n", queueId, strerror(errno));
return NULL;
}
if(ftruncate(queueFd, sizeof(* queue)) == -1) {
fprintf( stderr, "Queue resizing failed: %s\n",
strerror( errno ) );
return NULL;
}
/* on remplit la structure msgQueue */
queue->elemCounter = 0;
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strcpy(queue->headId,queue->id);
strcpy(queue->tailId,queue->id);
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// creation du semaphore
semaphore = sem_open(queueId, O_CREAT|O_EXCL, SEM_DEFAULT_MODE, 1);
if(semaphore == SEM_FAILED) {
NZG_ERROR("sem_open", queueId);
goto ERROR;
}
if(sem_wait(semaphore)==-1){
NZG_ERROR("sem_wait",queueId);
goto ERROR;
}
/* on ferme tout ce qu'il faut */
sem_close(semaphore);
close(queueFd);
return queue;
ERROR:
return NULL;
}