cmath compilation error when compiling old C++ code in VS2010

Mike O'Malley picture Mike O'Malley · Jun 29, 2010 · Viewed 20.8k times · Source

I've inherited a few C++ files and an accompanying makefile, which I'm trying to bring into VS2010 as a solution. I've created an empty project and added the appropriate C++ and header (.hpp) files for one of the makefile targets.

When I try to compile the project, however, I immediately get a large number of C2061 (syntax error identifier) errors coming from cmath regarding acosf, asinf, atanf, etc.

The error line in cmath:

#pragma once
#ifndef _CMATH_
#define _CMATH_
#include <yvals.h>

#ifdef _STD_USING
   #undef _STD_USING
     #include <math.h>
   #define _STD_USING

#else /* _STD_USING */
   #include <math.h>
#endif /* _STD_USING */

#if _GLOBAL_USING && !defined(RC_INVOKED)

_STD_BEGIN
using _CSTD acosf; using _CSTD asinf;

The top block of the relevant C++ file (though named as a .C):

#include <fstream>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

using namespace std;

Followed by the main() function, which doesn't call any of the trig functions directly. This has to be something really obvious, but I'm missing it. Can anyone help?

Thanks!

Answer

KillianDS picture KillianDS · Jun 29, 2010

Are you sure it's compiling as C++? Most compilers will compile .C file as C and .cpp files as C++, compiling a C++ file with a C-compiler will probably fail.

Also, that code mixes oldstyle ('c') headers and newstyle ('c++') headers. It should be more like this (I doubt that is the error however).

#include <fstream>
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>

using namespace std;

That's all I can see with what you've given. But most of the time when you get errors in library files of C/C++ itself, it still is code of you that's wrong somewhere, like forgetting the ; after a class statement in a header file.