c语言实现查看进程是否存在

#include<unistd.h>
#include<sys/types.h>
#include<sys/wait.h>
#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#include<limits.h>

#define BUFSZ 150

void err_quit(char *msg)
{
perror(msg);
exit(EXIT_FAILURE);
}

int main(int argc, char *argv[])
{
FILE* fp;
int count;
char buf[BUFSZ];
char command[150];
sprintf(command, "ps -ef | grep **** | grep -v grep | wc -l" );

if((fp = popen(command,"r")) == NULL)
err_quit("popen");

if( (fgets(buf,BUFSZ,fp))!= NULL )
{
count = atoi(buf);
if(count  == 0)
printf("not found\n");
else
printf("process :tdv1 total is %d\n",count);
}
pclose(fp);
exit(EXIT_SUCCESS);
}