heap_init()

Purpose

Creates and initialises the heap used by DP4 functions.

Syntax

void heap_init(size_t size);

Parameters

size_t size

size of the heap required

Description

This function works very differently for 16 and 32 bit programs.

• In 16 bit programs heap_init() creates a heap area by reducing the size of the stack by the amount specified or by the maximum possible if size is set to 0 bytes. The stack may be reduced to a maximum of 4KBytes, so this function is inappropriate if your program needs a larger stack. If heap_init() is used in a program, it is necessary to increase the size of the stack explicitly. For a DP4 program you can call:

  KENTCURS -MAXSTACK

  or

  KENTCURS -STACK <nnnn>

  Alternatively, you can specify a larger stack at link time.

  If enabled, Compiler stack checking is unaffected by this operation, i.e. it will cause a fault if your program uses more than the new 4K stack limit.

• For 32 bit programs the function works by calling the underlying C implementation of malloc() (or possibly an OS function like HeapAlloc()). If 0 is passed as the size, the size specified in the global variable df_heap_size is used. You can declare and initialise this variable yourself. The default df_heap_size is quite small - a little below 64K bytes.

Return values

None

See also

freex()