Function Error handling

Cicode Programming Reference > Using Cicode Programming Standards > Function Error handling

Function Error handling

Errors are handled by examining the return values of the functions. The Cicode functions can be classified as regards their return value as follows:

Functions returning	Calling functions should check for
Error code only	0 no error (success) > 0 error code
Handles	-1 bad handle >= 0 valid handle
Random values	the return of IsError()

Functions returning

Calling functions should check for

Error code only

0 no error (success)

> 0 error code

Handles

-1 bad handle

>= 0 valid handle

Random values

the return of IsError()

The following Cicode functions can halt the current task:

DevOpen, DevHistory, DevNext, DevPrev, DevSeek, DevFind, DevFlush, DevRecNo, DevRead, DevReadLn, DevAppend, DevDelete, DevZap, DevControl , DevPrint , DevModify, ErrTrap; FileOpen, FileClose, FileReadBlock, FileWriteBlock, FileSeek, FileDelete, FileReName, FileSize, FileReadLn, FileCopy; FormNew; SQLConnect, SQLTraceOn, SQLTraceOff, SQLErrMsg.

If an error is detected in one of these functions, your Cicode task will generate a hardware error and be halted. You may stop your Cicode task from being halted by using the ErrSet() function and checking for errors using IsError().

The parameter [Code]HaltOnError allows you to stop any errors detected in these functions from halting your Cicode. If you set. . .

[code]

HaltOnError=0

then your Cicode will continue to run after a hardware error is detected in these functions.

For example:

Example of error code only

INT

FUNCTION

ExampleInit()

   INT	 nError   = 0;

	 nError = ExampleOpen("MyForm");

   IF nError = 0 THEN

				...

	 END	 

END

INT

FUNCTION

ExampleOpen(STRING sName)

   INT	 nError   = 0;

	 ...

	 IF <an error has been detected> THEN

				nError = 299;

	 END

	 RETURN nError;

END

Example of handles

INT

FUNCTION

ExampleInit()

   INT	 hFile   = BAD_HANDLE;

	 ...

	 hFile = ExampleFileOpen("MyFile.txt");

	IF hFile <> BAD_HANDLE THEN

		 ...

	 END

END

FUNCTION

ExampleFileOpen(STRING sName)

	 INT	 hFile = BAD_HANDLE;

	 hFile = FileOpen(sName, "r+");

	IF hFile = BAD_HANDLE THEN

				hFile = FileOpen(sName, "r");

	 END

	 RETURN hFile;

END

Example of random values

INT

FUNCTION

ExampleInit()

   INT	 nSamples		= 0;

	...

	 ErrSet(1);

		nSamples = ExampleSamples();

	IF IsError() = 0 THEN

			 ...

	 END

	 ErrSet(0); 				

END

INT

FUNCTION

ExampleSamples()

	INT	 nSamples = 0;

	 INT	 nError   = 0;

	 ...

	 ErrTrap(nError);

  RETURN nSamples;

END