National Instruments Window - Manual (Page 30)

LabWindows/CVI Release Notes for Windows 30 © National Instruments Corporation
The ReturnRS232Err function is multithread safe. It returns the error value (zero if
successful) from the most recent RS-232 activity in the same thread.
Because ComWrt can return before all bytes in the output queue have been written to the port,
a write error can occur after ComWrt returns successfully. If ReturnRS232Err is then called,
it returns a value that reflects the write error. The rs232err global variable does not reflect
the write error.
For these reasons, National Instruments recommends that you always use ReturnRS232Err
instead of the rs232err global variable.
If you want to know the error associated with a particular function call, save the return value
from the function call in a variable.
Multithreading Limitations
Do not use XModemReceive or ComToFile in two threads at the same time if the target file
in both calls is the Standard Output.
Changes to the DDE Library
This section contains information on changes to the DDE Library and corrections to the
documentation.
Corrections
In the previous version of the manual, the order of topicName and itemName parameters in
the
BroadcastDDEDataReady function prototype is incorrect. The topicName is the second
parameter, and the itemName is the third parameter.
Obsolete Error Codes
Table 5 lists obsolete DDE Library error codes that are removed from ddesupp.h .
Table 5. Obsolete DDE Library Error Codes
Obsolete Code Defined Constant
–6 –kDDE_ReadFailed
–7 –kDDE_WriteFailed
–8 –kDDE_ExecutionFailed
–11 –kDDE_TimeOutErr
–13 –kDDE_FailedToSetUpHotLink
–14 –kDDE_FailedToSetUpWarmLink