NAME
          alloc - allocate memory

     SYNTAX
          #include <alloc.h>

          char *alloc(new);

          void alloc_free(x);

          void alloc_re(&x,old,new);

          char *x;
          unsigned int old;
          unsigned int new;

     DESCRIPTION
          alloc allocates enough space from the heap for new bytes of
          data, adequately aligned for any data type.  new may be 0.
          alloc returns a pointer to the space.  If space is not
          available, alloc returns 0, setting errno appropriately.

          alloc_free returns space to the heap.

          alloc_re expands the space allocated to x from old bytes to
          new bytes.  It allocates new space, copies old bytes from
          the old space to the new space, returns the old space to the
          heap, and changes x to point to the new space.  It then
          returns 1.  If space is not available, alloc_re returns 0,
          leaving the old space alone.

     SEE ALSO
          sbrk(2), malloc(3), error(3)