NI DAQMX Error Handling

Error Handling

• DAQmxGetErrorString
• DAQmxGetExtendedErrorInfo

DAQmxGetErrorString

int32 DAQmxGetErrorString (int32 errorCode, char errorString[], uInt32 bufferSize);

Purpose

Converts the error number returned by an NI-DAQmx function into a meaningful error message.

If you pass in a valid value for errorString and its bufferSize, this function returns as much of the available data as possible.

If you pass NULL for errorString or 0 for bufferSize, this function returns the number of bytes you need to allocate.

Parameters

Input
Name	Type	Description
errorCode	int32	An error code or warning returned by one of the NI-DAQmx Library functions.
bufferSize	uInt32	The size, in bytes, of the buffer passed in the errorString. If you pass 0, this function returns the number of bytes you need to allocate.
Output
errorString	char []	The meaningful error message for the error number. If you pass NULL, this function returns the number of bytes you need to allocate.

Return Value

Name	Type	Description
status	int32	The error code returned by the function in the event of an error or warning. A value of 0 indicates success. A negative value indicates an error. If you pass in a valid value for errorString and its bufferSize, this function returns as much of the available data as possible. If you pass NULL for errorString or 0 for bufferSize, this function returns the number of bytes you need to allocate.

DAQmxGetExtendedErrorInfo

int32 DAQmxGetExtendedErrorInfo (char errorString[], uInt32 bufferSize);

Purpose

Returns dynamic, specific error information. This function is valid only for the last function that failed; additional NI-DAQmx calls may invalidate this information.

If you pass valid values for errorString and bufferSize, this function returns as much of the available data as possible.

If you pass NULL for errorString or 0 for bufferSize, this function returns the number of bytes you need to allocate.

Parameters

Input
Name	Type	Description
bufferSize	uInt32	The size, in bytes, of errorString. If you pass 0, this function returns the number of bytes you need to allocate.
Output
Name	Type	Description
errorString	char []	Dynamic error information. If you pass NULL, this function returns the number of bytes you need to allocate.

Return Value

Name	Type	Description
status	int32	The error code returned by the function in the event of an error or warning. A value of 0 indicates success. A negative value indicates an error. If you pass in a valid value for errorString and its bufferSize, this function returns as much of the available data as possible. If you pass NULL for errorString or 0 for bufferSize, this function returns the number of bytes you need to allocate.