分叉時引起的錯誤

Question

我有下面的代碼，它分叉了兩個新進程，將一個標準輸出的內容保存到一個文件中。它運行得很好並保存文件，但在調用函數中返回以下行（不管它是什麼）後，會引發EXC_BAD_ACCESS錯誤。爲什麼？

void test(vector<string> inp,int i){ 
    int fds[2]; // file descriptors 
    long count; // used for reading from stdout 
    int fd;  // single file descriptor 
    char c;  // used for writing and reading a character at a time 
    pid_t pid; // will hold process ID; used with fork() 

    pipe(fds); 

    // child process #1. 
    fd = open((inp[i+1]).c_str(), O_RDWR | O_CREAT, 0666); 
    if (fork() == 0) { 
     if (fd < 0) { 
      return; 
     } 

     dup2(fds[0], 0); 

     // Don't need stdout end of pipe. 
     close(fds[1]); 

     // Read from stdout... 
     while ((count = read(0, &c, 1)) > 0) 
      write(fd, &c, 1); // Write to file. 

     exit(0); 
     // child process #2 
    } else if ((pid = fork()) == 0) { 
     dup2(fds[1], 1); 

     // Don't need stdin end of pipe. 
     close(fds[0]); 

     // Output contents of the given file to stdout. 
     char **arguments = getArguments(inp[i]); 
     execvp(arguments[0], arguments); 
     perror("execvp failed"); 
     exit(0); 
     // parent process 
    } else { 
     waitpid(pid, NULL, 0); 
     close(fds[0]); 
     close(fds[1]); 
    } 
} 

Answer 1

這很適合我：

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

void test(/*vector<string> inp,int i*/){ 
    int fds[2]; // file descriptors 
    long count; // used for reading from stdout 
    int fd;  // single file descriptor 
    char c;  // used for writing and reading a character at a time 
    pid_t pid; // will hold process ID; used with fork() 

    pipe(fds); 

    // child process #1. 
    fd = open(/*(inp[i+1]).c_str()*/"/tmp/output", O_RDWR | O_CREAT, 0666); 
    if (fork() == 0) { 
     if (fd < 0) { 
      return; 
     } 

     dup2(fds[0], 0); 

     // Don't need stdout end of pipe. 
     close(fds[1]); 

     // Read from stdout... 
     while ((count = read(0, &c, 1)) > 0) 
      write(fd, &c, 1); // Write to file. 

     _exit(0); 
     // child process #2 
    } else if ((pid = fork()) == 0) { 
     dup2(fds[1], 1); 

     // Don't need stdin end of pipe. 
     close(fds[0]); 

     // Output contents of the given file to stdout. 
     char **arguments = new char*[2];/*getArguments(inp[i]);*/ 
     arguments[0]=(char*)"/bin/bash"; 
     arguments[1]=0; 
     execvp(arguments[0], arguments); 
     perror("execvp failed"); 
     _exit(0); 
     // parent process 
    } else { 
     waitpid(pid, NULL, 0); 
     close(fds[0]); 
     close(fds[1]); 
    } 
} 

int main(int argc, char* argv[]){ 
    test(); 
} 

試着告訴正是出現在你的錯誤或表現出更多的程序的，這樣我就可以嘗試複製你的條件。