编写了一个多线程程序:
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#include <unistd.h>
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#include <stdio.h>
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`C4xj*V'o.?pthread_key_t key;
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$K } R(MC,gLinux伊甸园论坛void echomsg(int t)
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{
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printf("线程退出.\n");
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}
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oG:TV2Exk)S"__void *child1(void *arg) //为每一个线程单独建一个执行函数
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int tid=pthread_self(); //求线程id号
z K1f&R:\1h\&h(ARLinux伊甸园论坛 printf("thread %d enter\n",tid);
!^ dy*x |&a Tj pthread_setspecific(key,(void *)tid); //将tid的值与key相关联,注意不是*tid
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printf("thread %d returns %d \n", tid , pthread_getspecific(key)); //读出key值,即*tid?
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return NULL;
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void *child2(void *arg)
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{
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int tid=pthread_self();
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printf("thread %d enter\n",tid);
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pthread_setspecific(key,(void *)tid); //将tid的值与key相关联,注意不是*tid
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sleep(1);
/MT,B J O,\0Z6J E Hz printf("thread %d returns %d \n", tid , pthread_getspecific(key)); //读出key值,即*tid?
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return NULL;
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}
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int main()
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{
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int tid1,tid2; //线程号
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pthread_key_create(&key,echomsg); //注意在创建线程前创建私有数据,线程退出时会将key作为参数送入echomsg
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pthread_create(&tid1,NULL,child1,NULL); //创建线程,其中第一个NULL是设置线程属性,第二个NULL是child1函数的传人参数.线程的作用就是执行child1.
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pthread_create(&tid2,NULL,child2,NULL);
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%Ee y0t(f pthread_key_delete(key); //释放TSD
.j2k o k9PEy-g printf("main thread exit\n");
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}
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编译时总提示
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/tmp/ccFXz8Ip.o(.text+0xde): In function `child2':
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mythread.c: undefined reference to `pthread_setspecific'
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/tmp/ccFXz8Ip.o(.text+0xfc):mythread.c: undefined reference to `pthread_getspecific'
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/tmp/ccFXz8Ip.o(.text+0x166): In function `main':
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mythread.c: undefined reference to `pthread_key_create'
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/tmp/ccFXz8Ip.o(.text+0x17b):mythread.c: undefined reference to `pthread_create'
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/tmp/ccFXz8Ip.o(.text+0x190):mythread.c: undefined reference to `pthread_create'
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/tmp/ccFXz8Ip.o(.text+0x1ae):mythread.c: undefined reference to `pthread_key_delete'
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K$n;]GZ(}2{y)XLinux伊甸园论坛另外用gcc -Ipthread -Wall mythread.c -o mythread也没有用;
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;{8~'\ ic'X.Y谢谢大家.
