下面这个程序希望得到的结果是每5秒调用suvA(),suvB()每10秒调用suvC，suvD，就是出现suvA(),suvB()的次数是出现suvC，suvD次数的两倍，不知道为什么不行，应该怎么修改才可以。请高手们指点一下，谢谢。 编译环境linux

出现的结果是5秒suva，suvb，5秒suvc，suvd然后循环！

#include<iostream>
#include <pthread.h>
#include<time.h>

using namespace std;

void *suvA( void *ptr) {
sleep(5);
cout<<"it is suva"<<endl;

}

void *suvB( void *ptr) {
sleep(5);
cout<<"it is suvb"<<endl;

}

void *suvC( void *ptr) {
sleep(10);
cout<<"it is suvc"<<endl;

}

void *suvD( void *ptr) {
sleep(10);
cout<<"it is suvd"<<endl;

}

main()
{


int thread_ret1, thread_ret2, thread_ret3, thread_ret4;
pthread_t thread1, thread2, thread3, thread4;

while(true){

thread_ret1=pthread_create( &thread1, NULL, &suvA, NULL);
thread_ret2=pthread_create( &thread2, NULL, &suvB, NULL);
thread_ret3=pthread_create( &thread3, NULL, &suvC, NULL);
thread_ret4=pthread_create( &thread4, NULL, &suvD, NULL);

pthread_join( thread1, NULL);
pthread_join( thread2, NULL);
pthread_join( thread3, NULL);
pthread_join( thread4, NULL);


}

}