linux下怎么获取另一进程ID（编程实现）

linux下如何获取另一进程ID（编程实现）
我需要在一个程序中获取另一个进程PID，应该如何实现？
我知道可以用命令：ps -ax | grep "进程名" | awk '{print $1}'
不过需要用C语言实现，应该怎么做？
请大家指教，谢谢！

[解决办法]
system("ps -ax ¦ grep "进程名" ¦ awk '{print $1}' ")
[解决办法]

C/C++ code

 #include <unistd.h>#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <dirent.h>#include <string.h>#include <stdlib.h>#include <stdio.h>#define MAXLINE 1024int isdir(char *path){ struct stat buf; if(lstat(path,&buf)<0)  {//       printf("lstat err for %s \n",path);       return 0;   }  if(S_ISDIR(buf.st_mode)||S_ISLNK(buf.st_mode))  {    return 1;  }   return 0;}char * getfile(char *path){ static char filename[MAXLINE]; char *tmp1,*tmp2,filepath[MAXLINE]; if(path==NULL)return NULL; memset(filepath,0,sizeof(filepath)); strcpy(filepath,path); tmp2=tmp1=strtok(filepath,"/"); while((tmp1=strtok(NULL,"/"))) {  tmp2=tmp1; }memset(filename,0,sizeof(filename));if(tmp2){strcpy(filename,tmp2);tmp1=filename;while(*tmp1&&*tmp1++!=' ');*(tmp1)='\0';}else return NULL;return filename;}char* readstatus(char *filename){FILE *file;static char buf[MAXLINE];file=fopen(filename,"r");if(!file)return NULL;while(fgets(buf,sizeof(buf),file)){  if(strncmp(buf,"State",5)==0)        {                printf("%s\n",buf);                break;        }}fclose(file);}int main(int argc,char ** argv){char buf1[MAXLINE],buf2[MAXLINE];char path1[MAXLINE],path2[MAXLINE],*ptr,*str;DIR *db,*directory;struct dirent *p;if(argc!=2){printf("input file name .\nusage %s : filename \n",argv[0]);return 0;}db=opendir("/proc/");if(db==NULL)return -1;while ((p=readdir(db)))  {    if((strcmp(p->d_name,".")==0)||(strcmp(p->d_name,"..")==0))       continue;    else     {        memset(buf1,0,sizeof(buf1));        sprintf(buf1,"/proc/%s",p->d_name);        if(isdir(buf1))        {          memset(buf2,0,sizeof(buf2));          sprintf(buf2,"%s/exe",buf1);          if(access(buf2,F_OK)==0)          {                memset(path1,0,sizeof(path1));                if(readlink(buf2,path1,sizeof(path1))==-1)                continue;                ptr=getfile(path1);                if(strcmp(ptr,argv[1])==0)                {                       memset(path2,0,sizeof(path2));                       sprintf(path2,"%s/status",buf1);                       ptr=readstatus(path2);                }          }        }     } }closedir(db);}
[解决办法]
把结果写进临时文件，再读进来吧

不知道有没有什么更好的办法

ps好像也是循环去遍历/proc/目录下的进程的

stat64("/proc/5", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0
open("/proc/5/stat", O_RDONLY)          = 7
read(7, "5 (kswapd) S 1 1 1 0 -1 2112 0 0"..., 1023) = 131
close(7)                                = 0
open("/proc/5/status", O_RDONLY)        = 7
read(7, "Name:\tkswapd\nState:\tS (sleeping)"..., 1023) = 290
close(7)                                = 0
open("/proc/5/cmdline", O_RDONLY)       = 7
read(7, "", 2047)                       = 0
close(7)                                = 0
open("/proc/5/environ", O_RDONLY)       = 7
read(7, "", 2047)                       = 0
close(7)                                = 0 
 
stat64("/proc/6", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0