自学linux.信号量实验
#include <unistd.h>#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/sem.h>
#define KEY (key_ t)14010322
union semun{
int val;
struct semid_ ds *buf;
unsigned short *arry;
};
static int sem_ id= 0;
static int set_ semvalue();
static void del_ semvalue();
static void semaphore_ p();
static void semaphore_ _v();
int main(int argc, char *argv[]) {
int semid;
int product= 1;
int i;
if(-1 == (semid = semget(KEY,3,IPC_ _CREAT|0660))) {
print("ERROR\n");
gso
return -1;
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union semun arg;
arg.val= 1; //mutex= 1;
arg.val= 5; //empty= 5;
arg.val= 0; //full= 0;
for(i=0;i<3;i++){
semctl(semid, i, SETVAL, arg); .
for(i=0;i < 3;i++){
printf("The semval(%d) = %d\n",i,semctl(semid,i,GETVAL,NUL);
}
pid_ t p1,p2;
if(0 == (p1 = fork()){
while(1) {
semaphore_ p(semid,1);//P(empty)
printf("1\n");
semaphore_ .p(semid,0);//P(mutex)
printf("2\n");
product++;
printf("Producer %d: %d things",getpid(),product);
semaphore_ _v(semid,0);//V(mutex);
semaphore_ v(semid,2);//N(ul);
sleep(2);
}
}else {
if(0 == (p2 = fork()){
while(1){
sleep(2);
semaphore_ p(semid,2);// p(full)
printf("3\n");
semaphore_ .p(semid,0);//p(mutex)
printf("4\n");
product--;
printf("Consumer1 %d: %d things' ',getpid(),product);
semaphore_ v(semid,0);
semaphore_ _v(semid,1);
sleep(5);
}
}else{
while(1){
sleep(2);
semaphore_ .p(semid,2);//p(ulI)
printf("5\n");
semaphore_ _p(semid,0);//p(mutex)
printf("6\n");
product--; .
printf("Consumer2 %d: %d things ',getpid()product);
semaphore_ _v(semid,0);
semaphore_ v(semid,1);
sleep(5);
}
}
}
}
static void del_ semvalue() {
union semun sem_ union;
if(-1 == semctl(sem_ _id, 0, IPC_ RMID, sem_ union))
fprintf(stderr, "Failed to delete semaphore\n");
}
static int set_ semvalue() {
union semun sem_ union;
sem_ union.val= 1;
if(-1 == semctl(sem_ id, 0, SETVAL, sem_ _union))
return 0;
9
return 1;
必
}
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void semaphore_ .p(int sem_ id, int semNum) {
struct sembuf sem_ b;
sem_ b.sem_ num = semNum;
sem_ b.sem_ _op= -1; //P()
sem_ _b.sem_ _flg = SEM_ UNDO;
if (-1 == semop(sem_ id, &sem_ b, 1)) {
fprintf(stderr, "semaphore_ p failed\n");
}
}
void semaphore_ _v(int sem_ id, int semNum) {
struct sembuf sem_ b;
sem b.sem num = semNum;
sem_ b.sem_ op= 1; //N()
sem_ _b.sem_ _flg = SEM_ UNDO;
if(-1 == semop(sem_ id, &sem_ _b, 1)) {
fprintf(stderr, "semaphore_ p failed\n");
} 哇，这代码格式
{:5_108:}
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