以下是客户端

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

#define BUFFER_SIZE 1000
#define SER_PORT 3999

struct send_data_buffer
{
char buffer[BUFFER_SIZE];
pthread_mutex_t lock;
pthread_cond_t send_data_able;
pthread_cond_t write_data_able;
int buffer_full;
};

struct receive_data_buffer
{
char buffer[BUFFER_SIZE];
pthread_mutex_t lock;
pthread_cond_t receive_data_able;
pthread_cond_t read_data_able;
int buffer_empty;
};

char ser_IP[]={"192.168.0.115"};
struct send_data_buffer *send_buffer;
struct receive_data_buffer *receive_buffer;

void send_buffer_init(struct send_data_buffer *b)
{
pthread_mutex_init(&b->lock,NULL);
pthread_cond_init(&b->send_data_able,NULL);
pthread_cond_init(&b->write_data_able,NULL);
b->buffer_full=0;
}

void receive_buffer_init(struct receive_data_buffer *b)
{
pthread_mutex_init(&b->lock,NULL);
pthread_cond_init(&b->receive_data_able,NULL);
pthread_cond_init(&b->read_data_able,NULL);
b->buffer_empty=1;
}

void *transmission(void *data)
{
 pid_t child1,child2;
 int sockfd, numbytes,status1,status2; 
 char buf[BUFFER_SIZE];
 struct hostent *he;
 struct sockaddr_in ser_addr;  
  if((he=gethostbyname(ser_IP))==NULL)
 { 
  herror("gethostbyname error"); 
  exit(1); 
 }
 if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
 { 
  perror("socket create error"); 
  return; 
 }
 ser_addr.sin_family = AF_INET; 
 ser_addr.sin_port = htons(SER_PORT); 
 ser_addr.sin_addr = *((struct in_addr *)he->h_addr); 
 bzero(&(ser_addr.sin_zero),8); 
 if (connect(sockfd, (struct sockaddr *)&ser_addr, sizeof(struct sockaddr)) == -1)
 {
  perror("connect error"); 
  return;
 }
 if(!(child1=fork()))
  {
  int len;
  while(1)
  {
  pthread_mutex_lock(&send_buffer->lock);
while(send_buffer->buffer_full==0)
{
  pthread_cond_wait(&send_buffer->send_data_able,&send_buffer->lock);
}
len = strlen(send_buffer->buffer);
  if (send(sockfd,send_buffer->buffer,len, 0) == -1)
   {
    perror("send error"); 
return;
   }
send_buffer->buffer_full=0;
pthread_cond_signal(&send_buffer->write_data_able);
pthread_mutex_unlock(&send_buffer->lock);
  }
exit(0);
  }
 if(!(child2=fork()))
  {
  char buf[BUFFER_SIZE];
  while(1)
  {
 if (( numbytes = recv(sockfd, buf, BUFFER_SIZE, 0)) == -1||numbytes==0)
 { 
  perror("recv error"); 
 }
 buf[numbytes] = '';
 pthread_mutex_lock(&receive_buffer->lock);
 while(receive_buffer->buffer_empty==0)
  {
 pthread_cond_wait(&receive_buffer->receive_data_able,&receive_buffer->lock);
  }
 strcpy(receive_buffer->buffer,buf);
 receive_buffer->buffer_empty=0;
 pthread_cond_signal(&receive_buffer->read_data_able);
 pthread_mutex_unlock(&receive_buffer->lock);  
}
  }
 waitpid(child1,&status1,0);
 waitpid(child2,&status2,0);
 close(sockfd);
 return; 
}


void *infor_format(void *data)
{
pid_t child1,child2;
int status;
if(!(child1=fork()))
{
char buf[BUFFER_SIZE]; 
while(1)
{
gets(buf);
//buf=strcat("client send:",buf);
//buf=strcat(buf,'n');
  pthread_mutex_lock(&send_buffer->lock);
while(send_buffer->buffer_full==1)
{
  pthread_cond_wait(&send_buffer->write_data_able,&send_buffer->lock);
}
strcpy(send_buffer->buffer,buf);
send_buffer->buffer_full=1;
pthread_cond_signal(&send_buffer->send_data_able);
pthread_mutex_unlock(&send_buffer->lock);
}
}
if(!(child2=fork()))
{
char buf[BUFFER_SIZE];
while(1)
{
 pthread_mutex_lock(&receive_buffer->lock);
 while(receive_buffer->buffer_empty==1)
  {
 pthread_cond_wait(&receive_buffer->read_data_able,&receive_buffer->lock);
  }
 
 strcpy(buf,receive_buffer->buffer);
// buf=strcat("client receive:",buf);
// buf=strcat(buf,'n');
 puts(buf);
 receive_buffer->buffer_empty=1;
 pthread_cond_signal(&receive_buffer->read_data_able);
 pthread_mutex_unlock(&receive_buffer->lock);
}
}
 waitpid(child1,&status,0);
 waitpid(child2,&status,0);
 close(sockfd);
}

int main(void)
{
pthread_t th_a,th_b;
void *retval;
send_buffer_init(send_buffer);
receive_buffer_init(receive_buffer);
pthread_create(&th_a,NULL,transmission,0);
pthread_create(&th_b,NULL,infor_format,0);
pthread_join(th_a,&retval);
pthread_join(th_b,&retval);
return 0;
}




以上我写的SOCKET通信的客户端 能编译通过 
但是在运行的时候出现了“段错误”的提示
高手帮下忙 这是怎么回事

没有给
struct send_data_buffer *send_buffer; 
struct receive_data_buffer *receive_buffer; 
这两个指针分配内存

struct send_data_buffer *send_buffer;
struct receive_data_buffer *receive_buffer; 

这两个指针没有进行初始化，你后面的操作是对其进行空指针操作，所以会报段错误。

pintf打印输出，或者gdb调试，段错误一般是你内存操作溢出。很容易找到

一般来说段错误是指针问题造成的