我正在使用pthread库来创建两个线程.我使用两个队列来传递两个线程(生产者 – 消费者)之间的数据,因此希望有一个互斥体来同步线程中队列中的push-pops.
但我得到一个编译错误如下：
- $gcc simple-tun.c simple-tun -lpthread
- simple-tun.c: In function ‘new_queue’:
- simple-tun.c:920:13: error: expected expression before ‘{’ token
- 908 struct queue * new_queue () {
- 909
- 910 struct queue * q;
- 911 q = (struct queue *) malloc (sizeof(struct queue));
- 912
- 913 if (q == NULL)
- 914 return NULL;
- 915
- 916
- 917 q->head = NULL;
- 918 q->tail = NULL;
- 919 q->is_empty = 1;
- 920 q->mutex = PTHREAD_MUTEX_INITIALIZER;
- 921
- 922 return q;
- 923 }
结构队列是：
- struct queue {
- 80 struct node * head;
- 81 struct node * tail;
- 82 int is_empty;
- 83 pthread_mutex_t mutex;
- 84 };
- $gcc simple-tun.c simple-tun -lpthread
- simple-tun: In function `settun':
- (.text+0x2b7): multiple definition of `settun'
- /tmp/cc5Ms4xP.o:simple-tun.c:(.text+0x1cb): first defined here
- simple-tun: In function `_fini':
- (.fini+0x0): multiple definition of `_fini'
- /usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/crti.o:(.fini+0x0): first defined here
- simple-tun: In function `mktun':
- (.text+0x1e2): multiple definition of `mktun'
- /tmp/cc5Ms4xP.o:simple-tun.c:(.text+0xf6): first defined here
- simple-tun: In function `net_connect':
- (.text+0xe27): multiple definition of `net_connect'
- /tmp/cc5Ms4xP.o:simple-tun.c:(.text+0x1115): first defined here
- simple-tun: In function `data_start':
- (.data+0x0): multiple definition of `__data_start'
- /usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/crt1.o:(.data+0x0): first defined here
- simple-tun: In function `client_connect':
- (.text+0xe95): multiple definition of `client_connect'
- /tmp/cc5Ms4xP.o:simple-tun.c:(.text+0x1183): first defined here
- simple-tun: In function `data_start':
- (.data+0x8): multiple definition of `__dso_handle'
- /usr/lib/gcc/x86_64-linux-gnu/4.7/crtbegin.o:(.data+0x0): first defined here
- simple-tun:(.rodata+0x0): multiple definition of `_IO_stdin_used'
- /usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/crt1.o:(.rodata.cst4+0x0): first defined here
- simple-tun: In function `server_connect':
- (.text+0xfa2): multiple definition of `server_connect'
- /tmp/cc5Ms4xP.o:simple-tun.c:(.text+0x1290): first defined here
- simple-tun: In function `print_usage':
- (.text+0xe05): multiple definition of `print_usage'
- /tmp/cc5Ms4xP.o:simple-tun.c:(.text+0x10f3): first defined here
- simple-tun: In function `_init':
- (.init+0x0): multiple definition of `_init'
- /usr/lib/gcc/x86_64-linux-gnu/4.7/../../../x86_64-linux-gnu/crti.o:(.init+0x0): first defined here
- /usr/lib/gcc/x86_64-linux-gnu/4.7/crtend.o:(.tm_clone_table+0x0): multiple definition of `__TMC_END__'
- simple-tun:(.data+0x10): first defined here
- /usr/bin/ld: error in simple-tun(.eh_frame); no .eh_frame_hdr table will be created.
- collect2: error: ld returned 1 exit status
我无法在搜索中找到解决方案.我的代码有什么根本原因吗？有人能帮助我发现我做错了吗？
如果我需要发布更多片段或更多输出,请告诉我.
解决方法
>您不能像这样使用PTHREAD_MUTEX_INITIALIZER – 它必须用作初始值设定项,而不是常规赋值表达式.您有两种方法可以解决它 – 调用pthread_mutex_init()或添加类型转换以使用PTHREAD_MUTEX_INITIALIZER作为复合文字.您的选择：
- pthread_mutex_init(&q->mutex,NULL);
要么：
- q->mutex = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
- gcc simple-tun.c simple-tun -lpthread
你错过了-o,所以你试图将程序与自己联系起来.那是个坏消息.你可能想要的是：
- gcc simple-tun.c -o simple-tun -lpthread
实际上,你也应该在那里添加一些警告标志.
