Is there a way to use fopen_s() with GCC or at least create a #define about it?

Question

Hi, MSVC compiler says that fopen() is deprecated and recommends the use of fopen_s()...

Is there any way to use fopen_s() and still be portable?

Any ideas for a #define?

Thanks.

Answer 1

Microsoft's *_s functions are unportable, I usually use equivalent C89/C99 functions and disable deprecation warnings (#define _CRT_SECURE_NO_DEPRECATE).

If you insist, you can use an adaptor function (not necessarily a macro!) that delegates fopen() on platforms that don't have fopen_s(), but you must be careful to map values of errno_t return code from errno.

errno_t fopen_s(FILE **f, const char *name, const char *mode) {
    errno_t ret = 0;
    assert(f);
    *f = fopen(name, mode);
    /* Can't be sure about 1-to-1 mapping of errno and MS' errno_t */
    if (!*f)
        ret = errno;
    return ret;
}

However, I fail to see how fopen_s() is any more secure than fopen(), so I usually go for portability.

Answer 2

A similar issue here.