Heap allocation supports deallocation of allocated memory in any order. Dictionary allocation is not affected by it (i.e., it does not end a contiguous region). In Gforth, these words are implemented using the standard C library calls malloc(), free() and resize().
The memory region produced by one invocation of
resize is internally contiguous. There is no contiguity between
such a region and any other region (including others allocated from the
allocateu – a-addr wior memory “allocate”
Allocate u address units of contiguous data space. The initial contents of the data space is undefined. If the allocation is successful, a-addr is the start address of the allocated region and wior is 0. If the allocation fails, a-addr is undefined and wior is a non-zero I/O result code.
freea-addr – wior memory “free”
Return the region of data space starting at a-addr to the system.
The region must originally have been obtained using
resize. If the operational is successful, wior is 0.
If the operation fails, wior is a non-zero I/O result code.
resizea-addr1 u – a-addr2 wior memory “resize”
Change the size of the allocated area at a-addr1 to u
address units, possibly moving the contents to a different
area. a-addr2 is the address of the resulting area.
If the operation is successful, wior is 0.
If the operation fails, wior is a non-zero
I/O result code. If a-addr1 is 0, Gforth's (but not the Standard)
allocates u address units.