Compiler problem with c-code in Matlab

[sanctus]

I have a Matlab code which works fine in windows. Now I installed Xubuntu (because this way I have admin rights(=root) which I don't have on windows) and want to use the same code.

To be able to use the C-code you have to compile it from Matlab comand line with the comand

mex myfile.c

where before with mex -setup you define which compiler to use, the only choice I had was gcc (version 4.something).

Now if I compile I get the following error:

>> mex givegradient.c
Warning: You are using gcc version "4.1.2".  The earliest gcc version supported
with mex is "3.4.0".  The latest version tested for use with mex is "3.4.5".
To download a different version of gcc, visit http://gcc.gnu.org 
givegradient.c:2: error: expected identifier or ‘(’ before ‘/’ token
givegradient.c:16: error: expected identifier or ‘(’ before ‘/’ token
givegradient.c:142: error: expected declaration specifiers or ‘...’ before ‘/’ token
givegradient.c:143: error: expected declaration specifiers or ‘...’ before ‘/’ token
givegradient.c:144: error: expected declaration specifiers or ‘...’ before ‘/’ token
givegradient.c:147: error: conflicting types for ‘mexFunction’
/usr/local/matlab/extern/include/mex.h:148: error: previous declaration of ‘mexFunction’ was here
givegradient.c: In function ‘mexFunction’:
givegradient.c:156: error: ‘nrhs’ undeclared (first use in this function)
givegradient.c:156: error: (Each undeclared identifier is reported only once
givegradient.c:156: error: for each function it appears in.)
givegradient.c:159: error: ‘prhs’ undeclared (first use in this function)
givegradient.c:159: warning: assignment discards qualifiers from pointer target type
givegradient.c:166: error: ‘plhs’ undeclared (first use in this function)

    mex: compile of 'givegradient.c' failed.

??? Error using ==> mex
Unable to complete successfully.

And the first lines of my code have just the usual comments, i.e.:

/* $Revision: 1.1 $ */
// Automatically generated by Matlab AppWizard version 1.0
//
// This is the gateway routine for a MATLAB Math/Graphics Library-based
// C MATLAB MEX File.


#include "mex.h"
#include <math.h>
#define K 10.0
#define MAX(A,B) ((A)>(B)?(A):(B))
#define MIN(A,B) ((A)<(B)?(A):(B))
#define SGN(A) ((A)>0?1.:-1.)
#define ABS(A) ((A)>0?(A):-(A))

etc.

I can post also the rest of the code if needed...

I think it must be a compiler thing because the code worked with no problems on windows...
Thanks for any help

[sanctus]

With some help from someone at work I figures it out, in order to have it seen as a C++ file you have to name the file as *.cc or *.cpp and then it works fine....