One call to pthread_create implies 3 processes with ps

Hi all,
I begin using pthreads on a linux platform (RH7). My program creates 1 thread which is accepting lines from the standard input. It works but when I execute "ps -af", I see 3 instances of my process. I thought it would be at most 2.
Why are there 3 processes ?
Is there other commands than ps to list threads of a process on linux ?

Program:

#include <stdio.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
void *start(void *arg) {
char line[128];
  printf("thread pid %d\n", getpid()) ;
  while (1)     {
    printf("Data>");
    if (fgets(line, sizeof(line), stdin) == NULL) break ;
    if (strlen(line) <= 1) break ;
    printf("line [%s]\n", line) ;
  }
  return NULL ;
}
int main (int argc, char ** argv) {
  pthread_t mThreadId ;
  int status ;
  status = pthread_create(&mThreadId, NULL, start, NULL) ;
  if (status != 0)
  {
    printf("pthread_create failed, error %d", status) ;
  }
  printf("main pid %d\n", getpid()) ;
  status = pthread_join(mThreadId, NULL) ;
  if (status != 0)
  {
    printf("pthread_join failed, error %d", status) ;
  }
}

Compilation and execution:
# gcc -o thc -lpthread -g thread.c
# thc                    
main pid 14430
thread pid 14432
Data>
Data>sdgqg
line [sdgqg
]
Data>
#

Process list:
# ps -af |grep thc                          
root     14388 13912  0 13:58 pts/3    00:00:00 thc
root     14389 14388  0 13:58 pts/3    00:00:00 thc
root     14390 14389  0 13:58 pts/3    00:00:00 thc

With gdb, it also seems to have 3 threads/processes:
# gdb thc
...
This GDB was configured as "i386-redhat-linux"...
(gdb) r
Starting program: /home/sylvie/essais/thread/thc
[New Thread 1024 (LWP 14415)]
[New Thread 2049 (LWP 14416)]
[New Thread 1026 (LWP 14417)]
thread pid 14417
Data>main pid 14415

Thanks for help,
Sylvie