alloca(3) - NetBSD Manual Pages

ALLOCA(3)               NetBSD Library Functions Manual              ALLOCA(3)


NAME

     alloca -- memory allocator


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <stdlib.h>

     void *
     alloca(size_t size);


DESCRIPTION

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


RETURN VALUES

     The alloca() function returns a pointer to the beginning of the allocated
     space.  If the allocation failed, a NULL pointer is returned.


SEE ALSO

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


BUGS

     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.

NetBSD 4.0                      August 11, 2002                     NetBSD 4.0