Question

这是我的代码。当我尝试编译时，它给了我很多错误。我使用了gcc -o process process.c -lpthread。谁能帮我？我试过了“mamespace”，但这并没有帮助。

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>


int main()
{
  int i, j;
  int Num_of_children = 0;
  pid_t pid[10];
  pid_t return_pid;

  return_pid = fork();
  if(return_pid > 0) {
     pid[Num_of_children] = return_pid;
     Num_of_children = Num_of_children + 1;
  }

  return_pid = fork();
  if(return_pid > 0) {
     pid[Num_of_children] = return_pid;
     Num_of_children = Num_of_children + 1;
  }
  else { Num_of_children = 0; }

  if (Num_of_children > 0) {
     return_pid = fork();
     if(return_pid > 0) {
        pid[Num_of_children] = return_pid;
        Num_of_children = Num_of_children + 1;
     }
     else { Num_of_children = 0; }
  }
   for(j=0; j<3; j++) {
      sleep(1+1000*rand()/RAND_MAX);
      printf("PID: %d, Iteration: d%\n", getpid(), i);
   }
  for(j=0; j<Num_of_children; j++) waitpid(pid[j], NULL, 0);
}

Answer 1

在启用警告的情况下构建您的程序，即gcc -Wall -g -lpthread process.c -o process。然后，您将在代码中找到您所犯的错误：

process.c: In function ‘main’:
process.c:38:7: warning: unknown conversion type character 0xa in format [-Wformat=]
       printf("PID: %d, Iteration: d%\n", getpid(), i);
       ^
process.c:38:7: warning: too many arguments for format [-Wformat-extra-args]
process.c:41:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
process.c:38:7: warning: ‘i’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       printf("PID: %d, Iteration: d%\n", getpid(), i);
       ^

所以修复错误并重建它。

在Linux中执行线程程序

1 个答案: