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     The alloca routine allocates <size> bytes from the program's
     stack. The allocated space is automatically freed when the calling
     function is exited.
 
     Use of the alloca function is not recommended. The function is
     supported only for source compatibility with earlier releases.
     Routines using alloca should be compiled with optimization
     turned off (i.e., with the /Od option).
 
     When you compile with optimization on (either by default or by
     using one of the /O options), the stack pointer may not be
     restored properly in functions that have no local variables and
     also reference the alloca function. To ensure that the stack
     pointer is properly restored, make sure that any function
     referencing alloca declares at least one local variable.
 
     The pointer value returned by alloca should never be passed as an
     argument to the free function, nor should alloca be used in an
     expression that is an argument to a function.
 
     Return Value
 
     The alloca routine returns a void pointer to the allocated space,
     which is guaranteed to be suitably aligned for storage of any type
     of object. To get a pointer to a type other than void, use a type
     cast on the return value. The return value is NULL if the space
     cannot be allocated.
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