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

c gcc visual-c++ fopen
Shantia picture Shantia · Oct 3, 2009 · Viewed 25.9k times · Source

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?

Answer

Alex B picture Alex B · Oct 3, 2009

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.

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