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How do I define a constant in C ++?

I have executed a linux program on windows via Mingw. However, the transformation was not perfect. For example, on Windows, this is the output (I get "zu" instead of real numbers):

Approximated minimal memory consumption:
Sequence        : zuM
Buffer          : 1 X zuM = zuM
Table           : 1 X zuM = zuM
Miscellaneous   : zuM
Total           : zuM

It turns out Mingw doesn't support% zu, but it does offer a workaround. The website says:

This won't work since you are using Microsoft's implementation. Use mingw_printf directly or define USE_MINGW_ANSI_STDIO to 1 up to including stdio.h.

So, I did a search in my program and I found that cdhit-common.h is the only file that has the #include line. So, I defined USE_MINGW_ANSI_STDIO above this line and compiled:

#include<iostream>
#include<fstream>
#include<iomanip>
#include<cstdlib>
#define USE_MINGW_ANSI_STDIO 1
#include<stdio.h>
...

It compiles, but the program still prints "zu" instead of numbers. It's okay, what have I done? Why didn't it work?

Note. The solution with USE_MINGW_ANSI_STDIO is for mingw64 while I am using mingw. I hope for both platforms.

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2 answers


Macros, which I managed to install it now - is: __USE_MINGW_ANSI_STDIO

. Try it.



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You are setting the pre-processor flag. This means that when the compiler reads <stdio.h>

, it will have USE_MINGW_ANSI_STDIO

it set to 1. This will potentially be used in a compiler directive #if

or #ifdef

.

It is usually preferable to put these flags in your flag compilations, eg.

-DUSE_MINGW_ANSI_STDIO=1

rather than code.

(Note: it may be -D__USE_MINGW_ANSI_STDIO=1

)



If you put it in code, do it either

  • In a header that is always included before anything else, such as some platform related header.
  • Before other is included in your file.

It is possible that one of the C ++ stream headers implements using <stdio.h>

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