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我有一个程序，我正在编写一个全局定义的 File 变量，我试图在它派生一个孩子后由父级访问。但是，孩子是写入文件的那个，所以当我尝试作为父母阅读它时，我得到一个Error: No such file or directory. 只有它不会作为错误抛出，它存储在 tmpFP 文件中。我不知道如何解决这个问题。

为了便于阅读，我省略了一些代码，对套接字的引用来自自定义库，假设有效。相关评论应该全部大写，它们指出了我认为问题出现的地方。

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <unistd.h>
#include <stdarg.h>

#include "Socket.h"
#include "ToUpper.h" /* definitions shared by client and server */

#define LINE_SIZE 50
#define MAX_WORDS 10
#define MAX_LINE 1024
#define MAX_TMP 100
#define MAX_ARGS 4  /* allows program name + 3 positional parameters */
#define MIN_ARGS 2  /* must have at least 1 positional parameter */
#define NUM_PARMS 4  /* allows program name + 2 parameters + NULL */
#define ERR_RETURN -1

/* variables to hold socket descriptors */
ServerSocket welcome_socket;
Socket connect_socket;
char new_line[MAX_LINE];
char tmp_name[MAX_TMP]; //DECLARING FILENAME
char id_str[MAX_TMP];
char arr[LINE_SIZE]={0};
int id;
FILE *fp; //FILE USED IN CHILD PROCESS
void toupper_service(void);

int main(int argc, char* argv[])
{
    FILE *tmpFP; //FILE USED IN PARENT PROCESS

    pid_t spid; /* pid_t is typedef for Linux process ID */
    int c=0,index=0;
    id = (int) getpid();
    sprintf(id_str, "%d", id);
    strcpy(tmp_name,"tmp");
    strcat(tmp_name, id_str);
    if (argc < 2)
    {
        printf("No port specified\n");
        return (-1);
    }

    welcome_socket = ServerSocket_new(atoi(argv[1]));

    connect_socket = ServerSocket_accept(welcome_socket);
    Socket_close(welcome_socket);

    while (c!=EOF)
    {
        while((c=Socket_getc(connect_socket))!='\n')
        {
            arr[index]=c;
            index++;
        }
        arr[index]='\0';
        /* accept an incoming client connection; blocks the
         * process until a connection attempt by a client.
         * creates a new data transfer socket.
         */

        spid = fork();  /* create child == service process */
        if (spid == -1)
        {
            perror("fork");
            exit (-1);
        }
        if (spid == 0)
        {/* code for the service process */
            toupper_service();
            Socket_close(connect_socket);
            exit (0);
        } /* end service process */
        else /* daemon process closes its connect socket */
        {
            waitpid(spid,NULL,0); 

            //PASSES THIS TEST SOMEHOW 
            if((tmpFP = fopen (tmp_name, "r")) == NULL) 
            { 
                fprintf(stderr, "%s\n",tmp_name);
                fprintf (stderr, "error opening tmp file\n");
                exit (-1);
            }
            while((c=fgetc(tmpFP))!=EOF)
            {
                //PRINTS OUT ERROR HERE A LETTER AT A TIME 
                fprintf(stderr, "c: %d %c\n", c, (char)c); 
                Socket_putc(c, connect_socket);
            }
            remove(tmp_name);
            Socket_putc('\0', connect_socket);

            Socket_close(connect_socket);
            /* reap a zombie every time through the loop, avoid blocking*/
        }
    }/* end of infinite loop for daemon process */
    fprintf(stderr, "C: %d\n",c);
}
void toupper_service(void)
{
    int i=0, c, pointer,num_words=0,index=0;
    int too_many_words=0;
    char *word[MAX_WORDS]={NULL};

    //THIS IS THE OTHER PLACE TMP_NAME IS USED
    fp = freopen(tmp_name, "w", stdout); 

    while ((c=arr[index])!='\0')  
    {
        if(c==' '||c=='\t'||c=='\n') //word encountered
        {
            if(num_words>=MAX_WORDS-1)
            {
                printf("Too many commands passed\n");
                too_many_words=1;
                exit(0);
                break;
            }
            arr[index]='\0';
            word[num_words]=&arr[pointer];
            pointer=i+1;
            num_words++;
        }
        index++;
    }
    word[num_words]=NULL; 
    if(too_many_words==0)
    {
        c=0;
        int error=execvp(word[0],word);
    }
    return;
}
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