C++博客-newplan-随笔分类-UNIX Programming

五个哲学家线程实现

山泉弯延 — Thu, 03 Jan 2008 16:14:00 GMT

#include "apue.h"
#include "semaphore.h"
#include "pthread.h"

#define N 5
static int necs;
static sem_t  *forks;

void *
takeFork(int i)
{
if(i==N-1)
    {
     sem_wait(&forks[0]);
     sem_wait(&forks[i]);
    }
   else
     {
     sem_wait(&forks[i]);
     sem_wait(&forks[i+1]);
     }
}
void *
putFork(int i)
{
if(i==N-1)
    {
     sem_post(&forks[0]);
     sem_post(&forks[i]);
    }
else
    {
    sem_post(&forks[i]);
    sem_post(&forks[i+1]);
   }
}
void
thinking(int i,int necs)
{
    printf("pholosopher %d  is thinking\n",i);
    sleep(necs);

}
void
eating(int i,int necs)
{
    printf("pholosopher %d  is eating\n",i);
    sleep(necs);
}
void *
philosopher(void *n)
{
    int i=(int )n;
    while(1)
    {
     thinking(i,necs);
     takeFork(i);
     eating(i,necs);
     putFork(i);
    }
}
//============================main function
int
main(int argc,char *argv[])
{
   pthread_t tid;

   if(argc==1)
          necs=2;
   else if(argc ==2)
          necs=atoi(argv[1]);
   else return 1;

   forks=(sem_t*)malloc(N*sizeof(sem_t));

   int i;
   for(i=0;  i<N;  i++)
   sem_init(forks+i,0,1);

   int status;
   for(i=0;i<N;i++)
    {
      status=pthread_create(&tid,NULL,philosopher,(void*)i);

      if(status<0)
      err_sys("create error!");
    }
    pthread_join(tid ,NULL);
    return 0;
}

山泉弯延 2008-01-04 00:14 发表评论

五个哲学家进程实现

山泉弯延 — Thu, 03 Jan 2008 16:13:00 GMT

#include "apue.h"
#include "lock.h"
#include "lock.c"

/*define some important variable*/
/*=======================================*/
pid_t  pid;

static char *forks[5]={
"fork0", "fork1", "fork2" ,"fork3" ,"fork4"
};

static int necs;

#define N 5

/*======================================*/
void takeFork(int i)
{
if(i==N-1)
  {
     lock(forks[0]);
     lock(forks[i]);
  }
else
{
lock(forks[i]);
lock(forks[i+1]);
}
}

void putFork(int i)
{
   if(i==N-1)
    {
    unlock(forks[0]);
    unlock(forks[i]);
    }
  else
   {
   unlock(forks[i]);
   unlock(forks[i+1]);

   }
}
int
thinking(int i,int necs){
printf("pholosopher %d is thinking\n",i);
return sleep(necs);
}
int
eating(int i,int necs)
{printf("pholosopher %d is eating\n",i);
return sleep(necs);
}
void philosopher(int i)
{
while(1)
{
thinking(i,necs);
takeFork(i);
eating(i,necs);
putFork(i);

}
}
int
main(int argc ,char *argv[])
{
if(argc=1)
      necs=2;
else if(argc==2)
     necs=atoi(argv[1]);
else  return 0;

int i;
for(i=0;i<N;i++)
{
pid=fork();
if(pid ==0)
     philosopher(i);
}
return 0;
}

山泉弯延 2008-01-04 00:13 发表评论

同步写与异步写文件实现

山泉弯延 — Wed, 21 Nov 2007 10:45:00 GMT

/*
07.11.20 于海韵
*/
#include  "sys/times.h"
#include "apue.h"
#include "fcntl.h"
clock_t times(struct tms *buf);

static void pr_times(clock_t real ,struct tms *tmsstart, struct tms *tmsend);

int main(int argc, char *argv[])
{
  struct tms tmsstart,tmsend;

  clock_t  start,end;

  off_t excursion;

  if((excursion=lseek(0,0,SEEK_END))==-1)printf("can not seek!\n");

  char buf[excursion];

  /*printf("excutsion ==#%d\n",excursion);*/
  int outfile_fd;/*out file descrite tag */

  lseek(0,0,SEEK_SET);/*it is very importent  to go back  to the beginning of input file!*/

  if(read(0,buf,excursion)==0)printf("read OK!\n");
  /* buf[excursion]='\0';*/
  if(argc==3  &&  strcmp(argv[2],"sync")==0)
      { if(( outfile_fd=open(argv[1],O_RDWR|O_CREAT|O_SYNC,0666))<0)err_sys("creat error");}
    else if(argc==2)
       {if (( outfile_fd=open(argv[1],O_RDWR|O_CREAT,0666))<0)err_sys("creat error");}
    else{printf("para error!\n");exit(1);}
    long size=1024;
    fflush(stdin);
    printf("BUFFSIZE  USER CPU  SYSTEM CPU  REAL TIMES  CIRCLE TIMES\n");
    int  n;
    int t;
    char *p=buf;
    long  redo_count;/*re do copy times*/

  do{
      if((start=times(&tmsstart))==-1)err_sys("times error");
      redo_count=0;/*it is very import to set the counter zero at every circle */
      t=1;/*it is use in the inside while */
      while((n=write(outfile_fd,p,size))==size)
              {   p+=size;/*the begin buf must increase every time*/
                  redo_count++;/*count how many times circle do*/
                  t=size*redo_count;/*one tag to count how many charaters we have travered*/
                  /* printf("excursion==%d  t==%d   excursion-t==%d  size==%d\n",excursion,t,excursion-t,size);*/
                  if((excursion-t)<size)break;
              }
      if(excursion-t>0)
         if(write(outfile_fd,p,excursion-t)!=(excursion-t))err_sys("read error");
      if((end=times(&tmsend))==-1)err_sys("times error");
      printf("%7ld",size);
      pr_times(end-start,&tmsstart,&tmsend);
      printf("%7ld\n",redo_count);
      lseek(outfile_fd,0,SEEK_SET);/*let the outfile pointer go back to the beginning of outfile!*/
      p=buf;/*let p return to the beginning of buf;*/
     /* printf("size=%d  excursion=%d\n",size,excursion);*/
     } while((size*=2)<=excursion);

return 0;
}
static void
pr_times(clock_t real ,struct tms *tmsstart,struct tms *tmsend)
{static long clktck=0;
if(clktck==0)
if((clktck=sysconf(_SC_CLK_TCK))<0)
    printf("sysconf error");

printf("   %2.5f",(tmsend->tms_utime-tmsstart->tms_utime)/(double)clktck);
printf("   %2.5f",(tmsend->tms_stime-tmsstart->tms_stime)/(double)clktck);
printf("     %2.5f    ",real/(double)clktck);
}

山泉弯延 2007-11-21 18:45 发表评论

unix_简单shell实现

山泉弯延 — Tue, 06 Nov 2007 15:18:00 GMT

#include "apue.h"
#include <sys/wait.h>
extern  char **environ;
static void sign_Int(int signnal)
{printf("Be interrupted\n%%");}
static void sign_Quit(int signnal)
{printf("quit\n%%");
}

int
main(void)
{

    char *argv[20];
    pid_t pid;
    int status;
    if(signal(SIGINT,sign_Int)==SIG_ERR)
       err_sys("signal error\n");
    if(signal(SIGQUIT,sign_Quit)==SIG_ERR)
         err_sys("signal error\n");
    printf("%%");
    while (1)
    {        char buf[MAXLINE];
             int index=0,i=0;
           if(fgets(buf,MAXLINE,stdin)==NULL)
             break;
        while( buf[i] != '\0'&&buf[i]!='\n' )
        {
           if(buf[i] != ' ' )
           {
               argv[index]= buf+i;
               index++;
               for(;buf[i]!= ' '&&buf[i]!='\n';i++);
               if(buf[i]=='\n')
               break;
               buf[i]='\0';
                i++;
                while(buf[i]==' ')
                       i++;
           }
        }
        buf[i]='\0';
        argv[index] = NULL;
        if((pid = fork() ) < 0 )
           err_sys("fork error\n");
        else if( pid == 0 )
        {
           execve(argv[0],argv,environ);
           err_ret("coundn't execute:%s",argv[0]);
           exit(127);
          }
        if(( pid = waitpid(pid,&status,0)) < 0)
           err_sys("waitpid error\n");
          printf("%%");
     }
     exit(0);
}

山泉弯延 2007-11-06 23:18 发表评论