进程间通信问题

made_in_chn

:help
求一段进程交互的代码, 给伪码也行
其实满基础的, 用fork或execl等都可以吧
:ask

开10个进程, 分别执行func01(), func02(), ... func10(),
分别return ret01, ret02, ... ret10
等十个都跑完了后, 再将ret01, ... ret10相加,
相加的结果作为最终返回值

rickxbx

homework? plz read some book like "Advanced Programming in the Unix Environment"

x11

进程间通讯的关键不是fork、execl吧，莫名中。。。

made_in_chn

差不多是homework级别的东东, 但不是homework
就是进程间通信不会阿...
那关键是啥?

made_in_chn

我写了段代码, 但不知道怎么锁文件, 用fcntl和semaphore都试了, 都有问题
大侠们帮帮忙啊...


/////////////////////
// test1.c
// gcc -o test1 test1.c
// ./test1
//////////////////////////////////////
/// how to lock file when writing? ///
//////////////////////////////////////

#include <unistd.h>
#include <stdio.h>
#include <sys/fcntl.h>
#include <sys/wait.h>
#define NPID 10

/////????????????
int mklock ()
{
  // i don't know how to implement that...
  return 0;
}

/////?????????????
int unlock ()
{
  // i don't know how to implement that...
  return 0;
}

int DoSth (int a)
{
  printf ("%ld is doing!!\n", getpid());
  sleep (1);
  return a*a;
}

int SaveToFile (char *filename, int nResult)
{
  int fd;
  char buf[10];
  FILE *fp;
  if ((fp = fopen(filename, "a")) == NULL) {
    printf ("fopen %s for append error\n", filename);
    return -1;
  }
  fprintf (fp, "%d ", nResult);
  fclose(fp);
  return 0;
}

int FileToArray(char *filename, int *arr)
{
  int nResult;
  int nCnt = 0;
  FILE *fp;
  if ((fp = fopen(filename, "r")) == NULL) {
    printf ("fopen %s for read error\n", filename);
    return -1;
  }
  while (!feof(fp)) {
    fscanf (fp, "%d ", &nResult);
    arr[nCnt] = nResult;
    nCnt++;
    printf ("%d ", nResult);
  }
  fclose(fp);
  return 0;
}

int main ()
{
  pid_t pid1;
  int n1, i;
  char filename[10];
  int nArr[NPID];
  FILE *fp;
  int status;

  sprintf (filename, "%ld.file", getpid());
  printf ("%s created!!\n", filename);
  if ((fp = fopen(filename, "w")) == NULL) {
    printf ("create %s error\n", filename);
    return -1;
  }
  fclose (fp);

  for (i=0; i<NPID; i++) {
    if ( (pid1 = fork()) < 0)
      return -1;
    if (pid1 == 0) {
      pid1 = getpid();
      n1 = DoSth (36+i);
      //////////????????///////////////////////////
      mklock();
      SaveToFile(filename, n1);
      unlock();
      //////////????????//////////////////////////
      return 0;
    }
  }
  wait (&status);
  sleep (1);
  FileToArray(filename, nArr);
  printf("================ %ld ==============\n", getpid());

  for (i=0, n1=0; i<NPID; i++) {
    n1 += nArr;
    printf ("pid[%d] = %d\n", i, nArr);
  }
  printf ("total = %d\n", n1);
  return 0;
}