User`s guide

10 Windows HLLAPI Functions
CHAPTER 2
WinHLLAPI Installation Checking
To detect the presence of any Windows HLLAPI implementations on a system, an application that has
been linked with the Windows HLLAPI Import Library can attempt to call the WinHLLAPIStartup( )
routine. Alternately, an application can examine the $PATH environment variable to search for
instances of Windows HLLAPI API implementations (WHLLAPI.DLL). For each instance, it can issue
a LoadLibrary( ) call and use the WinHLLAPIStartup( ) routine to discover implementation-specific
data.
This version of the Windows HLLAPI API specification does not attempt to address explicitly the issue
of multiple stacks/multiple concurrent Windows HLLAPI implementations. Nothing in the
specification should be interpreted as restricting multiple WinHLLAPI DLLs from being present and
from being used concurrently by one or more Windows HLLAPI application.
Byte Ordering
The Intel® byte ordering is like that of the DEC® VAX® and so differs from the Internet and 68000-
type processor byte ordering. Take care in your programming to ensure the correct orientation.
Deviation from IBM EHLLAPI
There are a few limited instances where Windows HLLAPI diverts from strict adherence to the IBM
EHLLAPI conventions. This deviation is due to the nature of the Windows graphical environment and
the way it differs from other HLLAPI platforms.
Error constants are consistent with IBM EHLLAPI to maintain backward compatibility with existing
software.
Window Handle Passed for Each Async Call
A Window handle has been added as the first parameter passed to the WinHLLAPIAsync entry point.
This allows the WinHLLAPIAsync implementation to distinguish between HLLAPI applications.
Pointers
All pointers used by applications with WHLLAPI should be FAR.
Blocking Routines
Although blocking functions are supported with Windows HLLAPI, you should not use them. Instead
you should use the WinHLLAPIAsync function in conjunction with a WinHLLAPIAsync Windows
message.
Programming with
Windows HLLAPI