osx man page for alloca

ALLOCA(3)						   BSD Library Functions Manual 						 ALLOCA(3)

NAME
     alloca -- memory allocator

SYNOPSIS
     #include <alloca.h>
     or
     #include <stdlib.h>

     void *
     alloca(size_t size);

DESCRIPTION
     The alloca() macro allocates size bytes of space in the stack frame of the caller.  This temporary space is automatically freed on return.

RETURN VALUES
     alloca() returns a pointer to the beginning of the allocated space.

SEE ALSO
     brk(2), calloc(3), getpagesize(3), malloc(3), realloc(3)

HISTORY
     alloca() appeared in Version 32V AT&T UNIX.

BUGS
     alloca() is machine and compiler dependent; its use is discouraged.

     alloca() is slightly unsafe because it cannot ensure that the pointer returned points to a valid and usable block of memory.  The allocation
     made may exceed the bounds of the stack, or even go further into other objects in memory, and alloca() cannot determine such an error.  Avoid
     alloca() with large unbounded allocations.

     The use of C99 variable-length arrays and alloca() in the same function will cause the lifetime of alloca's storage to be limited to the
     block containing the alloca()

BSD
								 September 5, 2006							       BSD