读写锁主要用于数据读操作比写操作频繁,且数据的实时性要求不高的场景
使用gcc 编译的时候加上参数 -lrt -lpthread
////////////////////////////////////////////////////server.c//////////////////////////////////////////////////////////////////////
#include <pthread.h>
#include <stdio.h>#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#define SHMFILENAME "rwlockdata.d"
struct RDWRLockData
{
pthread_rwlock_t rwLock;
int currentIndex;
};
int main(void)
{
int fd;
pthread_rwlockattr_t rwLockAttr;
struct RDWRLockData *sharedMemoryPtr;
int sharedmemoryLength=0;
sharedmemoryLength=sizeof(struct RDWRLockData);
fd=shm_open(SHMFILENAME,O_RDWR|O_CREAT|O_TRUNC,0777);
if(fd==-1)
{
printf("open shared memory failed!\n");
printf("error reason is :%s!\n",strerror(errno));
exit(0);
}
if(ftruncate(fd,sharedmemoryLength)