ANSI C Comaptibility

Question

I need a compiler that is ANSI C compatible for another program that I am using.  The developers of this other program have a test for whether the the compiler is ANSI C compliant.  The snippet below is compiled and run, and the answer appears in the console window.

#ifdef __STDC__
printf (“The compiler used to compile this code supports ANSI\n”);
#else
printf (“The compiler used to compile this code is non-ANSI\n”);
#endif
}

Of course, Visual Studio Express 2010 fails this test.  However, I was told by the on-line chat folks at Microsoft that it was ANSI C compliant.  Does anyone know if the problem is just some configuration setting that I need to change?  (Or is it really true that Microsoft Visual Studio Express has no <String.h> header file, like the error message I keep getting when I use this other program suggests?)

Answer 1

>Or is it really true that Microsoft Visual Studio Express
>has no <String.h> header file, like the error message I
>keep getting when I use this other program suggests?

There is a header named string.h in VC++ and in ANSI C.

If you are getting an error from an #include you need to
show the exact error message and the exact code.

>#ifdef __STDC__
>Visual Studio Express 2010 fails this test.

VC++ recognizes that predefined macro (manifest constant).
However, it is only defined when you build with the option
enabled to disable MS extensions. See:

Predefined Macros
http://msdn.microsoft.com/en-us/library/b0084kay%28v=vs.100%29.aspx

/Za, /Ze (Disable Language Extensions)
http://msdn.microsoft.com/en-us/library/0k0w269d.aspx

>I was told by the on-line chat folks at Microsoft that
>it was ANSI C compliant.

It is compliant with the ANSI/ISO C90 Standard.

- Wayne

Answer 2

In addition to what Wayne said, you can check what headers VC is shipped with yourself. They are in the VC directory itself.

By default this is %ProgramFiles%\Visual Studio 10.0\VC\include (this is %ProgramFiles(x86)% on 64 bit versions of Windows).

If you also want to test out whether it has this header, you can also just do a simple test application along the lines of:

#include <string.h>
int main()
{
    return 0;
}

and try to build it. Because of the entry point being main, this obviously requires a console application, but if this fails to compile because it can't find the header string.h then I would urge you to check your configuration.

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Any samples given are not meant to have error checking or show best practices. They are meant to just illustrate a point. I may also give inefficient code or introduce some problems to discourage copy/paste coding. This is because the major point of my posts is to aid in the learning process.

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