C2440 Error message?

[earnshaw]

Does anyone know what this error message means:

error C2440: '=' : cannot convert from 'void *' to 'char *'
Conversion from 'void*' to pointer to non-'void' requires an explicit cast...

The code which causes this error is:

tables[0] = malloc(strlen((table) +1) * sizeof(char));

Many thanks
Simon

[itsme86]

It means you're compiling C code with a C++ compiler.

[earnshaw]

Is there a way to get round it, I thought C code was compatible 99% more or less in C++ envionment....

[apsync]

change extension .cpp to .c

[itsme86]

I thought C code was compatible 99% more or less in C++ envionment

Congratulations, you found part of that 1% that's not compatible. If you're compiling C code you should use a C compiler. If you're compiling C++ code you should use a C++ compiler.

[Ken Fitlike]

>>Is there a way to get round it<<

You could tell your compiler to compile as C (/TC) regardless of the file extension of source files.

[earnshaw]

That sounds like a more sensible solution Ken - in the C/C++ tab in Property-> Settings, I cant find the advanced tab to tell VS to compile as C.
Do you know where it is?

Thanks

[earnshaw]

Actually, the example link you have provided refers to Visual Studio .NET, how do you set to compile C for version 6 of Visual Studio??

Can anyone help, it cant be that hard, although I still cant find the damn option

[elad]

How about just casting the void * returned by malloc() to type char * using the C casting syntax, like this:


tables[0] = (char *)malloc(strlen((table) +1) * sizeof(char));

Assuming tables is an array of char * that might work.

[Salem]

Just name your files properly.

[Thantos]

another solution that might work (haven't tested)

#ifdef __cplusplus
extern "C" {
#endif
tables[0] = malloc(strlen((table) +1) ); /* removed sizeof(char) since it will always be 1 */
#ifdef __cplusplus
}
#endif

[Salem]

I feel ill.....

[Thantos]

Its ok salem, the evil C++ will leave eventually

[quzah]

That sounds like a more sensible solution Ken - in the C/C++ tab in Property-> Settings, I cant find the advanced tab to tell VS to compile as C.
Do you know where it is?

Thanks

How is this more sensible than renaming your file? .C means C. .CPP means C++. What is not to understand here? Do what your compiler expects you to, and you won't have to jump through hoops to work around your intentional stupidity. And yes, at this point you're simply being stupid, because you've already been told what the problem is, so you cannot claim ignorance. You still refuse to use the correct resolution, preferring to concoct some crazy work around, rather than simply doing as you should. That's just being stupid.

Quzah.

[anonytmouse]

another solution that might work (haven't tested)

#ifdef __cplusplus
extern "C" {
#endif
tables[0] = malloc(strlen((table) +1) ); /* removed sizeof(char) since it will always be 1 */
#ifdef __cplusplus
}
#endif

extern "C" turns off name mangling, and by implication features which use name mangling such as function overloading. This allows extern "C" functions to be called from C, other programming languages and other compilers. The code is still compiled as C++. extern "C" can be thought of as a linker instruction.