Specifications

50 •• C/C++ & DLL Libraries
5.16 _7200_Alloc_DBDMA_Mem
@ Description
Contact Windows 95/98 system to allocate a block of contiguous
memory as circular buffer for double-buffered DMA DI transfer.
This function is only available in Windows 95/98 version. For
double-buffered transfer principle, please refer to Section 6
“Double Buffered Mode Principle”.
@ Syntax
Visual C++ (Windows 95/98)
int W_7200_Alloc_DBDMA_Mem (U32 *buff,U32 *handle, U32
buf_size, U32 *actual_size)
Visual Basic (Windows 95/98)
W_7200_Alloc_DBDMA_Mem (buff As Long, handle As Long,
ByVal buf_size As Long, actual_size As Long) As Long
@ Argument
buff : The is a dummy buffer attached to the DMA memory
this function will allocate. But this buffer need to
have size equal to or more than buf_size bytes.
handle: The handle of system DMA memory returned from
system. Use this handle in _7200_DI_DMA_Start.
buf_size: Bytes to allocate. This is the half size of circular
buffer in byte. That is, this is the size of each half
buffer in byte.
actual_size: The actual DMA memory size system allocate for
each half buffer. If system is not able to get a block
of contiguous memory of specified buf_size, it will
allocate a block of memory as large as it can. In this
case, this function returns
ERR_SmallerDMAMemAllocated, and actual_size
denotes the actual size of allocated memory for each
half of circular buffer.
@ Return Code
ERR_NoError
ERR_SmallerDMAMemAllocated