provider.c~

抽烟者问题。假设一个系统中有三个抽烟者进程

#include"ipc.h"

int main(int argc,char *argv[]){
   
   int con_val=0;//可控制轮换提供材料


   int rate;
   if(argv[1]!=NULL)rate=atoi(argv[1]);
   else rate=3;

   buff_key=101;
   buff_num=2;
   pput_key=102;
   pput_num=2;
   shm_flg=IPC_CREAT|0644;

   buff_ptr=(char*)set_shm(buff_key,buff_num,shm_flg);
   pput_ptr=(int *)set_shm(pput_key,pput_num,shm_flg);

   prod_key=201;
   pmtx_key=202;
   cig_key=301;
   pap_key=302;
   glu_key=303;
   smtx_key=304;
   sem_flg=IPC_CREAT|0644;

   sem_val=0;
   prod_sem=set_sem(prod_key,sem_val,sem_flg);

   sem_val=0;
   cig_sem=set_sem(cig_key,sem_val,sem_flg);
   pap_sem=set_sem(pap_key,sem_val,sem_flg);
   glu_sem=set_sem(glu_key,sem_val,sem_flg);

   sem_val=1;
   pmtx_sem=set_sem(pmtx_key,sem_val,sem_flg);

   while(1){
     down(prod_sem);
     down(pmtx_sem);

     if(con_val%3==0){
        sleep(rate);
        buff_ptr[*pput_ptr]='C';
        *pput_ptr=(*pput_ptr+1)%buff_num;
        buff_ptr[*pput_ptr]='P';
        printf("Provider supply PC\n");
        sleep(rate);
        }//送CP
     else if(con_val%3==1){
         sleep(rate);
         buff_ptr[*pput_ptr]='C';
        *pput_ptr=(*pput_ptr+1)%buff_num;
        buff_ptr[*pput_ptr]='G';
        printf("Provider supply GC\n");
        sleep(rate);
        }  //送CG
          else{ sleep(rate);
                buff_ptr[*pput_ptr]='P';
               *pput_ptr=(*pput_ptr+1)%buff_num;
                buff_ptr[*pput_ptr]='G';
                printf("Provider supply GP\n"); 
                sleep(rate);
               } //送PG 
     *pput_ptr=(*pput_ptr+1)%buff_num;

     up(pmtx_sem);
     if(con_val%3==0) up(glu_sem);
     else if(con_val%3==1) up(pap_sem);
          else up(cig_sem);

    con_val=(con_val+1)%3;
     
     }
   return EXIT_SUCCESS;
  }