dispatch_queue_t-queue-lock.m

#import "ViewController.h"
#import <AFNetworking/AFNetworking.h>

@interface ViewController ()

@end

static dispatch_queue_t _queue;
static dispatch_semaphore_t _semphore;

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    _queue = dispatch_get_global_queue(0, 0);
    
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    dispatch_async(_queue, ^{
        
        _semphore = dispatch_semaphore_create(1);
        for (int i = 0; i<10; i++) {
            dispatch_semaphore_wait(_semphore, DISPATCH_TIME_FOREVER);
            NSLog(@"start-----%zd", i);
            [self getNetwork: i];
            NSLog(@"end-----%zd", i);
        }
    });
}

- (void)getNetwork: (int) i {
    
    AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
    manager.responseSerializer = [AFHTTPResponseSerializer serializer];
    
    // request 1
    NSString* urlStr1 = @"http://www.weather.com.cn/data/sk/101010100.html";
    
    [manager GET:urlStr1 parameters:nil progress:^(NSProgress * _Nonnull uploadProgress) {
        
    } success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
        
//        NSDictionary* json = [NSJSONSerialization JSONObjectWithData:(NSData *)responseObject options:0 error:nil];
        NSLog(@"finishi-----------%zd", i);
        dispatch_semaphore_signal(_semphore);
        
    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
    }];
    
}


@end

/*
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 */