Why does the compiler still warn me about unsafe strtok even after I define _CRT_SECURE_NO_WARNINGS?

Question

I am using Visual Studio Express 2012 for Windows Desktop.

I always get error

Error C4996: 'strtok': This function or variable may be unsafe.
  Consider using strtok_s instead.
  To disable deprecation, use _CRT_SECURE_NO_WARNINGS.
  See online help for details.

When I try to build the following:

#include "stdafx.h"
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstring>
using namespace std;
int main() {
    char the_string[81], *p;
    cout << "Input a string to parse: ";
    cin.getline(the_string, 81);
    p = strtok(the_string, ",");
    while (p != NULL) {
        cout << p << endl;
        p = strtok(NULL, ",");
    }
    system("PAUSE");
    return 0;
}

Why am I getting this error even though I define _CRT_SECURE_NO_WARNINGS, and how do I fix it?

There is no question and no sense at all. Why not simply using `strtok_s` ? What's the problem ? — Blacktempel, Jan 10 '14 at 12:18
Your `#define` should in any case be *before* `#include "stdafx.h"` or alternatively put it in your project properties under C++/Preprocessor definitions. — Roger Rowland, Jan 10 '14 at 12:19
The solution is to 1) read the details in the online help, and 2) use `strtok_s` instead, as suggested - or use C++ functions instead of C. Do *not* switch off warnings. — molbdnilo, Jan 10 '14 at 13:00
@Blacktempel Because `strtok_s` is a proprietary library extension and thus not portable. — ComicSansMS, Jan 10 '14 at 13:51

score 7 · Answer 1 · answered Jan 10 '14 at 13:36

Your #define doesn't work because of the content of your precompiled header file (stdafx.h). The boilerplate one looks like this:

#pragma once
#include "targetver.h"
#include <stdio.h>
#include <tchar.h>

It is the last two #includes that cause the problem, those .h files themselves already #include string.h. Your #define is therefore too late.

Beyond defining the macro in the compiler settings instead, the simple workaround is to just move the #define into your stdafx.h file. Fix:

#pragma once
#define _CRT_SECURE_NO_WARNINGS
#include "targetver.h"
#include <stdio.h>
#include <tchar.h>

score 6 · Answer 2 · answered Dec 08 '16 at 09:30

6

This may be an old post but I had a similar problem recently. I went into the project options -> C/C++ -> Preprocessor -> added _CRT_SECURE_NO_WARNINGS to the list of Preprocessor Definitions. This way you don´t have to put it in every file.

answered Dec 08 '16 at 09:30

Martin

61
1
1

score 2 · Answer 3 · answered Jun 12 '18 at 04:24

2

Try following.

#pragma warning (disable : 4996)

Note the error number is C4996.

answered Jun 12 '18 at 04:24

getsuha

711
6
16

score -1 · Answer 4 · answered Jan 10 '14 at 12:22

-1

It looks like you switched on a compiler option that forces the compiler to consider all warnings as errors. Either switch off this option or indeed use macro _CRT_SECURE_NO_WARNINGS

answered Jan 10 '14 at 12:22

Vlad from Moscow

301,070
26
186
335

Why does the compiler still warn me about unsafe strtok even after I define _CRT_SECURE_NO_WARNINGS?

4 Answers4