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The latest version of this topic can be found at _msize.

Returns the size of a memory block allocated in the heap.

      size_t _msize(  
   void *memblock   


Pointer to the memory block.

_msize returns the size (in bytes) as an unsigned integer.

The _msize function returns the size, in bytes, of the memory block allocated by a call to calloc, malloc, or realloc.

When the application is linked with a debug version of the C run-time libraries, _msize resolves to _msize_dbg. For more information about how the heap is managed during the debugging process, see The CRT Debug Heap.

This function validates its parameter. If memblock is a null pointer, _msize invokes an invalid parameter handler, as described in Parameter Validation. If the error is handled, the function sets errno to EINVAL and returns -1.

RoutineRequired header

For more compatibility information, see Compatibility in the Introduction.

All versions of the C run-time libraries.

See the example for realloc.

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.

Memory Allocation