ID Number: Q23033
3.00
WINDOWS
Summary:
The Windows SDK (Software Development Kit) function NetBIOSCall is
provided as an interface for application developers using network
communication protocols.
More Information:
The NetBIOSCall translates to an interrupt 5Ch call and is handled by
the Virtual NetBIOS driver under 386 Enhanced Mode Windows or by the
DOS Extender (DOSX.EXE) under Standard Mode.
The interface provides for both synchronous and asynchronous NetBIOS
commands.
When asynchronous commands are used, there are two rules that an
application developer must follow:
1. The POST routine provided to the network control block (NCB)
MUST be in a FIXED code segment in a DLL (dynamic-link library).
This is necessary since the asynchronous event could complete
while a DOS operation is in progress. Since DOS is used to reload
segments, if the event occurred while in DOS, it would not be
possible to reload a not-present segment. A FIXED code segment in
a DLL remains fixed and page-locked in memory at all times.
2. The same principle applies to the NCB and associated read or write
buffers for asynchronous commands. These buffers should allocate
GMEM_FIXED.
It is recommended that synchronous commands not be used if a
comparable asynchronous command is available. Synchronous NetBIOS
commands cause the entire Windows system to halt until the command
completes.
Additional reference words: 3.00