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); 
}