process_1.c

linux下模拟进程互斥的一个小程序。

/* process_1.c */
#include "msgcom.h"
main()
{
  int a,b,m,qid;
  struct msgtype buf;
  buf.mtype=1;
  buf.text.appli_in=0;
  buf.text.appli_exit=0;
  qid=msgget(MSGKEY,IPC_CREAT|0666);
  printf (" *Process_1 request into eritical_sect !\n" );
  printf("    ------If other process using the eritical_sect ,must wait !\n ");
  
  msgsnd ( qid, &buf, sizeof(buf.text), 0 );
  msgrcv ( qid, &buf, 512, 2, MSG_NOERROR );
  
  if ( buf.text.appli_in==1 ) {
     printf ( " *The process_1 is in the eritical_sect !\n" );
     
     /* my program */
     printf ( " *Please input the vaule of a:");
     scanf ( "%d",&a );
     printf ( " *Please input the vaule of b:"); 
     scanf ( "%d",&b );
     m=a+b;
     printf ( " *THE RESULT IS : m=a+b=%d\n",m );      
     
     printf ( " *The process_1 is request to leave eritical_sect !\n" );
     buf.text.appli_exit=1;
     buf.mtype=3;
     msgsnd( qid, &buf, sizeof(buf.text), 0 );
     msgrcv( qid, &buf, 512, 4, MSG_NOERROR );
     printf ( " *The process_1 have left eritical_sect ! \n");
  }
    
  
}