获取终止进程的退出状态

Question

我正在尝试获取每个进程的退出状态以及它是否返回 1 或 0，并获取每个进程的总和（1 的数量和 0 的数量）。似乎最后一个返回 1 的进程是 while 循环中唯一正在等待的进程。

该程序将文件名作为命令行参数并确定它们是否存在。对于每个文件名（存在与否），一个新进程通过与父级的风扇关系派生，如果文件不存在，则返回错误状态。如果确实存在，则返回成功状态。然而，只有最后一个 PID 显示在 while 循环中。

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

    pid_t pid;
    int i, stat, suc = 0, fail = 0;

    if (argc < 2){
        printf("Usage: ./wordcount.exe [File_1] [File_2] [...] [File_n]\n");
        exit(1);
    }

    for (i = 1; i < argc; i++){

        if ((pid = fork()) == 0){

            if (access(argv[i], F_OK) != 0){
                fprintf(stderr, "Child process %ld for %s does not exist\n", (long)getpid(), argv[i]);
                return 1;           
            }
            fprintf(stderr, "Child process %ld for %s: Number of words is: %d\n", (long)getpid(), argv[i], 0);
            exit(0);
        }
    }

    while(1){

        if (waitpid(pid, &stat, 0) == -1 && errno != EINTR) {
            printf("pid var = %d\tstat=%d\n", pid, stat);
            fail++;
            break;
        } else {
            printf("pid var = %d\tstat=%d\n", pid, stat);
            suc++;
        }
    }

    printf("Parent process created %d processes to count %d words in %d files\n", (suc + fail), 0, (suc + fail));
    printf("%d file(s) have been counted successfully!\n", suc);
    printf("%d file(s) did not exist.\n", fail);

    return 0;
}

Current output with 2 existing files and 2 non-existing:

$ ./wordcount.exe input_file_1.txt input_file_2.txt inputfail1 inputfail2
Child process 3565 for input_file_1.txt: Number of words is: 0
Child process 3566 for input_file_2.txt: Number of words is: 0
Child process 3567 for inputfail1 does not exist
Child process 3568 for inputfail2 does not exist
pid var = 3568  stat=256
pid var = 3568  stat=256
Parent process created 2 processes to count 0 words in 2 files
1 file(s) have been counted successfully!
1 file(s) did not exist.

Answer 1

我综合了你们两个的帮助。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "restartwait.h"

char* ReadLine();

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

    pid_t pid[argc - 1];
    int i, stat, suc = 0, fail = 0;

    if (argc < 2){
        printf("Usage: ./wordcount.exe [File_1] [File_2] [...] [File_n]\n");
        exit(1);
    }

    for (i = 1; i < argc; i++){
        pid[i-1] = fork();
        if (pid[i-1] == 0){

            if (access(argv[i], F_OK) != 0){
                fprintf(stderr, "Child process %ld for %s does not exist\n", (long)getpid(), argv[i]);
                return 1;           
            }
            fprintf(stderr, "Child process %ld for %s: Number of words is: %d\n", (long)getpid(), argv[i], 0);
            return 0;
        } else if (pid[i-1] == -1){
            fprintf(stderr, "fork() returned an error. Exiting...\n");
            exit(1);
        } else {
            //parent
            //printf("I am the parent. PID: %d\n", getpid());
        }
    }

    int j=0;
    while (1){
        int x = wait(&stat);
        if (x == -1 && errno != EINTR){
            break;
        }
        //catch errors
        else if (x == -1){
            printf("-1\n");
            break;
        }

        if (stat == 0){
            suc++;
        } else if (stat > 0){
            fail++;
        }
        j++;
    }
    
    printf("Parent process created %d processes to count %d words in %d files\n", (suc + fail), 0, (suc + fail));
    printf("%d file(s) have been counted successfully!\n", suc);
    printf("%d file(s) did not exist.\n", fail);

    return 0;
}