National Instruments 320685D-01 ユーザーズマニュアル

Chapter 9

Checking for Errors in LabWindows/CVI

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 National Instruments Corporation

9-3

LabWindows/CVI Programmer Reference Manual

After your program detects an error, it must take some action to either correct the situation or 
prompt the user to select a course of action. The following example shows a simple error 
response function.

void ErrorCheck (char *errMsg, int errVal, char *errString)

{

char outputMsg[256];

int response;

Fmt (outputMsg, "%s (Error = %d).\n%s\nContinue? ",

errMsg,errVal,errString);

response = ConfirmPopup ("ErrorCheck", outputMsg);

if (response == 0) 

exit (-1);

}

This section describes how LabWindows/CVI libraries and instrument drivers report errors. 
Notice that libraries that return their status code using global variables or separate functions 
sometimes report additional status information through return values. 

The User Interface Library routines return a negative value when they detect an error. Some 
functions, such as 

LoadPanel

, return positive values for a successful completion. This 

library uses a common set of error codes, which the LabWindows/CVI User Interface 
Reference Manual and the function panel help list. You can use the function 

GetUILErrorString

 to get the error message associated with each User Interface Library 

error code. 

The Analysis and Advanced Analysis Library functions return a negative value when they 
detect an error. This library uses a common set of error codes, which the LabWindows/CVI 
Standard Libraries Reference Manual, the LabWindows/CVI Advanced Analysis Reference 
Manual, and the function panel help list. You can use the function 

GetAnalysisErrorString

 to get the error message associated with each Analysis Library 

error code. 

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