Hi,

I have few source files (.c) working perfectly fine in gcc. Now i have to change the extension to cpp. When I did that it gave me a whole bunch of errors. any suggestions ??

I do not quite understand what you want to do and why, anyway, C++ files (they might have .cpp extension) are compiled by 'g++'.

well .. i made a project using c language and used gcc compiler. Now i am being told that all those files should be a .cpp extension files. So i thought that just changing the file extension would do the trick but sadly its not. I tried using g++ and it gave me a pretty much the same errors...

Were you supposed to make the project in "C" or in C++ ? It's hard to believe someone would insist on "C" files having .cpp extension.

well i was told to make it in c but for some compatibility reason i need the file extension to be cpp instead of c. So does anyone know any trick

As sergei states in his first reply, use g++ instead of gcc.

Alternatively you can read up on the -x option (man gcc).

May we confirm that the project is being done under linux and not windows?

well,
C is not C++.
.cpp is a C++ extension.
g++ behaviour is not the same as gcc or cc.

things acceptable in C aren't in C++.
let me guess 'deprecated cast from const char * to char *' and such like?

you will probably need to edit the code.
some clues would be nice.

Maybe you misunderstood the instructions.

Maybe you are supposed to limit yourself to constructs that are valid in both C and C++. In that case, post the code and compile errors. Someone will probably tell you what aspect of the C code is invalid as C++.

If you are literally correct about those instructions (code in C but have the extension be cpp) then you can use the -x option in gcc as Wim Sturkenboom suggested.

gcc -x c file.cpp

Thank you guys, '-x c' is the thing I was looking for.

Just one last thing, can you tell me by doing so it would be following PURE c calling convention: like: when functions it would be passing all the parameters on the stack and will do NO name mangling like in c++

OS: Linux-32bit
Source files: C coding standard with cpp extension

I still think it is more likely you are misunderstanding the type of "compatibility" you are supposed to achieve and -x c is only what you think you were looking for, not what you should have been looking for.

But it's still nice to see this forum (Wim Sturkenboom in this case) can dredge up that kind of obscure answer so well. (I stopped reading Wim's post after his un helpful first line without seeing his helpful second line. I knew some such gcc option existed but no clue of details. So I skimmed through the man pages, found -x c, started to post that and only then noticed Wim already had.)

The -x c will entirely treat your .cpp input files as .c files:

It will use pure c calling convention, including NO name mangling because it is processing the input as C, not in any way as C++.

It will pass calling parameters on the stack (as opposed to in registers or by other means) but that is because it is x86 architecture, not because it is C rather than C++.

On an architecture, such as x86_64, where C++ passes parameters in other ways (not all on the stack), C passes parameters the same as C++.

Yeah I do understand what I am trying to achieve is kinda weird but this is what the requirements demand. I was being told to code up the project using C language, C calling conventions (cdecl = __attribute__ ((cdecl))) but with .cpp extension.

Anyhow, Thank you so much everyone for your help.