Invalid file handle

A file handle was used that isn't a valid open file.

This error usually indicates that a file handle was used after it was closed. An attempt to use a file handle that was never opened would be reported as an uninitialized variable error rather than an invalid file handle error. A file open operation that fails returns a null pointer. An attempt to use a file handle without checking that the open succeeded would be reported as a possible null pointer dereference error rather than an invalid file handle error.

When a file handle is closed, resources associated with that file are released. Using that file handle after it is closed can cause a reference to memory that has been freed. This can have unpredictable consequences, especially if that storage has been reused for another purpose.

ID	Code Location	Description
1	Use of invalid resource	The place where the invalid file handle was used

Example


#include <stdio.h>

int main(int argc, char **argv)
{
    FILE *fp;
    int data;
    fp = fopen("newfile", "w");
    if (fp != 0) {
        fclose(fp);
        data = fgetc(fp); // bad - file already closed
    }
}