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DispatchSemaphoreTest.m
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47 lines (36 loc) · 1.12 KB
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//
// DispatchSemaphoreTest.m
// WGFcodeNotes
//
// Created by 白菜 on 2022/10/10.
// Copyright © 2022 WG. All rights reserved.
//
#import "DispatchSemaphoreTest.h"
@interface DispatchSemaphoreTest()
@property(nonatomic, strong) dispatch_semaphore_t semp;
@end
@implementation DispatchSemaphoreTest
-(instancetype)init {
self = [super init];
if (self) {
//初始化信号量 最大并发数量是3
self.semp = dispatch_semaphore_create(3);
}
return self;
}
-(void)otherTest {
for (int i = 0; i < 20; i++) {
[[[NSThread alloc]initWithTarget:self selector:@selector(test) object:nil] start];
}
}
//最多有3个线程可以同时进来执行这个任务
-(void)test {
// 如果信号量的值 > 0, 让信号量的值减1，然后继续往下执行代码
// 如果信号量的值 <= 0，就会休眠等待，直到信号量的值 > 0,就让信号量的值减1，然后继续往下执行代码
dispatch_semaphore_wait(_semp, DISPATCH_TIME_FOREVER);
NSLog(@"%s",__func__);
sleep(1.0);
// 让信号量的值 + 1
dispatch_semaphore_signal(_semp);
}
@end