ALLOCA(3) BSD Library Functions Manual ALLOCA(3)
alloca -- memory allocator
Standard C Library (libc, -lc)
The alloca() function allocates size bytes of space in the stack frame of
the caller. This temporary space is automatically freed on return.
The alloca() function returns a pointer to the beginning of the allocated
space. If the allocation failed, a NULL pointer is returned.
brk(2), calloc(3), getpagesize(3), malloc(3), realloc(3)
The alloca() function is machine dependent; its use is discouraged.
The alloca() function 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.
BSD August 11, 2002 BSD