linux下的多线程编程常用函数

Linux下pthread的实现是通过系统调用clone（）来实现的。

clone（）是Linux所特有的系统调用，他的使用方式类似fork.int pthread_create(pthread_t *restrict tidp,const pthread_attr_t *restrict attr, void *(*start_rtn)(void),void *restrict arg); 返回值：若是成功建立线程返回0,否则返回错误的编号形式参数：pthread_t *restrict tidp 要创建的线程的线程id指针const pthread_attr_t *restrict attr 创建线程时的线程属性void* (start_rtn)(void) 返回值是void类型的指针函数void *restrict arg start_rtn的行参进行编译的时候要加上-lpthread向线程传递参数。

例程2：功能：向新的线程传递整形值#include <stdio.h>#include <pthread.h>#include <unistd.h>void *create(void *arg){int *num;num=(int *)arg;printf("create parameter is %d \n",*num);return (void *)0;}int main(int argc ,char *argv[]){pthread_t tidp;int error;int test=4;int *attr=&test;error=pthread_create(&tidp,NULL,create,(void *)attr);if(error){printf("pthread_create is created is not created ... \n");return -1;}sleep(1);printf("pthread_create is created ...\n");return 0; }编译方法：gcc -lpthread pthread_int.c -Wall执行结果：create parameter is 4pthread_create is created is created ...例程总结：能够看出来，我们在main函数中传递的整行指针，传递到我们新建的线程函数中。

在上面的例子能够看出来我们向新的线程传入了另一个线程的int数据，线程之间还能够传递字符串或是更复杂的数据结构。

例程3：程式功能：向新建的线程传递字符串程式名称：pthread_string.c#include <stdio.h>#include <pthread.h>#include <unistd.h>void *create(void *arg){char *name;name=(char *)arg;printf("The parameter passed from main function is %s \n",name);return (void *)0;}int main(int argc, char *argv[]){char *a="zieckey";int error;pthread_t tidp;error=pthread_create(&tidp, NULL, create, (void *)a);if(error!=0){printf("pthread is not created.\n");return -1;}sleep(1);printf("pthread is created... \n");return 0;}程式目的：验证新建立的线程能够共享进程中的数据程式名称：pthread_share.c#include <stdio.h>#include <pthread.h>#include <unistd.h>static int a=4;void *create(void *arg){printf("new pthread ... \n");printf("a=%d \n",a);return (void *)0;}int main(int argc,char *argv[]){pthread_t tidp;int error;a=5;error=pthread_create(&tidp, NULL, create, NULL);if(error!=0){printf("new thread is not create ... \n");return -1;}sleep(1);printf("new thread is created ... \n");return 0;}2、线程的终止假如进程中任何一个线程中调用exit，_Exit,或是_exit，那么整个进程就会终止，和此类似，假如信号的默认的动作是终止进程，那么，把该信号发送到线程会终止进程。

线程的正常退出的方式：(1) 线程只是从启动例程中返回，返回值是线程中的退出码(2) 线程能够被另一个进程进行终止(3) 线程自己调用pthread_exit函数两个重要的函数原型：#includevoid pthread_exit(void *rval_ptr);/*rval_ptr 线程退出返回的指针*/int pthread_join(pthread_t thread,void **rval_ptr);/*成功结束进程为0,否则为错误编码*/例程6程式目的：线程正常退出，接受线程退出的返回码程式名称：pthread_exit.c#include#include#includevoid *create(void *arg){printf("new thread is created ... \n");return (void *)8;}int main(int argc,char *argv[]){pthread_t tid;int error;void *temp;error = pthread_create(&tid, NULL, create, NULL);if( error ){printf("thread is not created ... \n");return -1;}error = pthread_join(tid, &temp);if( error ){printf("thread is not exit ... \n");return -2;}printf("thread is exit code %d \n", (int )temp);return 0;}线程退出能够返回线程的int数值。

线程退出不但仅能够返回线程的int数值，还能够返回一个复杂的数据结构。

例程7程式目的：线程结束返回一个复杂的数据结构程式名称：pthread_return_struct.c#include#include#includestruct menber{int a;char *b;}temp={8,"zieckey"};void *create(void *arg){printf("new thread ... \n");return (void *)&temp;}int main(int argc,char *argv[]){int error;pthread_t tid;struct menber *c;error = pthread_create(&tid, NULL, create, NULL);if( error ){printf("new thread is not created ... \n");return -1;}printf("main ... \n");error = pthread_join(tid,(void *)&c);if( error ){printf("new thread is not exit ... \n");return -2;}printf("c->a = %d \n",c->a);printf("c->b = %s \n",c->b);sleep(1);return 0;}3、线程标识函数原型：pthread_t pthread_self(void);pid_t getpid(void);getpid()用来取得现在进程的进程识别码,函数说明实现在新建立的线程中打印该线程的id和进程id程式名称：pthread_id.cvoid *create(void *arg){printf("New thread .... \n");printf("This thread's id is %u \n", (unsigned int)pthread_self());printf("The process pid is %d \n",getpid());return (void *)0;}int main(int argc,char *argv[]){pthread_t tid;int error;printf("Main thread is starting ... \n");error = pthread_create(&tid, NULL, create, NULL); if(error){printf("thread is not created ... \n");return -1;}printf("The main process's pid is %d \n",getpid());sleep(1);return 0;}。