由进程名获取pid

需要/proc文件系统支持

#include <stdio.h>
#include <unistd.h>
#include <dirent.h>
#include <sys.types.h>

#define MAXSIZE 124

pid_t getPidByName( char* name )
{
 DIR *dirHandle;
 struct dirent *dirEntry; // 单个目录项
 pid_t pid = -1;
 char strPathName[100];
 FILE *fp;
 char buff[MAXSIZE];

 memset(strPathName,'0',100);

 if( (dirHandle = opendir("/proc")) == NULL )
 {
  return -1;
 }

 chdir("/proc");
 while( (dirEntry = readdir(dirHandle)) != NULL)
 {
  if(dirEntry->d_name[0] != '.' && strcmp(dirEntry->d_name, "sys") !=0 )
  {
   sprintf(strPathName, "./%s/%s", dirEntry->d_name,"cmdline");
   if( (fp = fopen(strPathName,"r") ) == NULL)
   {
    printf("failed to open %s/n",strPathName);
    break;
   }

   memset(buff,'0',MAXSIZE);
   if( (int)fread(buff,MAXSIZE,1,fp) == -1)
   {
    printf("failed to read %s/n",strPathName);
    fclose(fp);
    break;
   }

   if( strcmp(buff,name) == 0)
   {
    pid = (pid_t)atoi(dirEntry->d_name);
   }
   fclose(fp);
  }
 }
 closedir(dirHandle);
 return pid;
}