how to check a file is close ? c

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C#

#include<stdio.h>
#include "file.h"
void openfilechk()
{
    char ch;
    fp = fopen("abc.txt","r");
    while( ( ch = fgetc(fp) ) != EOF )
    {
      printf("%c",ch);
    }
//    fclose(fp);
    printf("file readed \n");
    if (fclose(fp) == 0)
    {
                       //close was successful
    //    fp = 0;     // this ensures you the file is closed
        printf("\nFILE SUCCESSFULLY CLOSED\n");
    }
}
int main()
{
    openfilechk();
    if (fp == NULL)
    {
                       //close was successful
    //    fp = 0;     // this ensures you the file is closed
        printf("\nFILE SUCCESSFULLY CLOSED\n");
    }
    return 0;
}

portion inside main is not validating whether a file is closed?

file.h

FILE *fp;

Posted 22-Jan-13 19:51pm

mvigsnhwar

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Marius Bancila 23-Jan-13 2:51am

What is openfilechk() supposed to do? If you're not setting fp to NULL, what's the point of checking it later in main(). You need to explain what you want to do.

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OriginalGriff · Answer 1 · 2013-01-22T21:05:00

You openfilechk function does not change fp to indicate the closed status. As a result, if it opened sucessfully, it always leaves it indicating the file block you opened.

C#

#include<stdio.h>
#include "file.h"
void openfilechk()
{
    char ch;
    fp = fopen("abc.txt","r");
    while( ( ch = fgetc(fp) ) != EOF )
    {
      printf("%c",ch);
    }
    printf("file readed \n");
    if (fclose(fp) == 0)
    {
                       //close was successful
        fp = NULL;     // this ensures you the file is closed
        printf("\nFILE SUCCESSFULLY CLOSED\n");
    }
}
int main()
{
    fp = NULL;         // Give it an initial value
    openfilechk();
    if (fp == NULL)
    {
                       //close was successful
        printf("\nFILE SUCCESSFULLY CLOSED\n");
    }
    return 0;
}

BTW: It's a style thing, but I wouldn't declare variables in a ".h" file - constants, and structure definitions only.
I'd also return fp from the openfilechk method and store it in a local variable rather than using a global anyway - that way you can use it for two different files in the future. In the case of a function defined to check if it was possible to open teh file, I'd return a bool rather than a FILE* anyway - it makes your code a lot more readable.