Error message: undefined symbol _msize in C

Question

I m Writing program for dynamic memory allocation. In this program i getting error of undefined symbol _msize. I have also include . Please help me with this.

/* Example of _msize */

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>

void main()
{
 long *buffer;
 size_t size;

 buffer = (long *)malloc(100 * sizeof(long));
 size = _msize(buffer);
 printf("The size of the buffer is %d\n", size);
}

This is a non-portable thing from Microsoft. Are you using the MSVC compiler? — Mat, Nov 24 '17 at 08:29
_msize() is not the standard function of C. It looks like home cooked stuff. You need to include the right header file in order to use that. Find _msize() in which header file it’s located. Side note: don’t use void main() that is not part of the C standard. — danglingpointer, Nov 24 '17 at 08:29
@LethalProgrammer..In header file, this function is already there. I have included that one also. http://www.digitalmars.com/rtl/stdlib.html#_msize — , Nov 24 '17 at 08:32
Is the header file you use meant to be used for the environment you use for building? I.e. matching compiler, all needed libraries linked implicitly or explicitly. — Yunnosch, Nov 24 '17 at 08:33
1. TurboC++ is an outdated antiquated product. 2. TurboC++ obviously doesn't have `_msize`. 3. `_msize` is not standard. 4. `_msize` isn't needed at all, you can do everything you want without it. 5. why is `_msize`not needed? Because _you_ allocated the buffer so you obviously know the size. — Jabberwocky, Nov 24 '17 at 08:50
This is clearly a linker error and does not come from the compiler — Jens Gustedt, Nov 24 '17 at 08:59

score 1 · Answer 1 · answered Nov 24 '17 at 08:34

The _msize is not Standard C.

It is from Microsoft Visual C++(MSVC), and you need to include <malloc.h>, as you already did, and use a Microsoft Compiler (e.g. within the Visual Studio).

PS: Unrelated to your problem: What should main() return in C and C++?

Error message: undefined symbol _msize in C

1 Answers1