我正在编写一个程序,它使用信号量和信号量缓冲区来实现并行编程中的互斥。下面是导致错误的代码,以及使用sembuf指针的信号和等待函数。
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdlib.h>
#include <unistd.h>
#include <semaphore.h>
#include <pthread.h>
#define NSEMS 1
// semaphore buffers
static struct sembuf OP = {0,-1,0};
static struct sembuf OV = {0,1,0};
struct sembuf *P =&OP;
struct sembuf *V =&OV;
// Wait() function for semaphore
int POP()
{
int status;
status = semop(sem_id, P,1);
return status;
}
// Signal() function for semaphore
int VOP()
{
int status;
status = semop(sem_id, V,1);
return status;
以下是我收到的错误:
sem.c:17:15: error: variable ‘OP’ has initializer but incomplete type
static struct sembuf OP = {0,-1,0};
^
sem.c:17:15: warning: excess elements in struct initializer [enabled by default]
sem.c:17:15: warning: (near initialization for ‘OP’) [enabled by default]
sem.c:17:15: warning: excess elements in struct initializer [enabled by default]
sem.c:17:15: warning: (near initialization for ‘OP’) [enabled by default]
sem.c:17:15: warning: excess elements in struct initializer [enabled by default]
sem.c:17:15: warning: (near initialization for ‘OP’) [enabled by default]
我收到OV结构的相同错误,我不明白为什么。非常感谢任何帮助。
答案 0 :(得分:2)
在使用类型...
之前,您需要包含必要的标题在你的情况下:
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>