First off information about my setup.
NI-daq 8.1.0f1
Windows XP SP2
No National Instruments devices currently connected, for testing.
The function DAQmxGetErrorString does not behave defined in the daqmxcfunc.chm file located in NI-DAQ\Docs folder.
In the documentation it says for the 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. |
However this is not what it returns. Below I have example code to demonstrat this.
#include <NIDAQmx.h>
#include <iostream>
int main(int argc, char *argv)
{
int32 size;
int32 error = -2147220712;
char *msg = new char[100];
char msg2[100];
size = DAQmxGetErrorString(error, msg2, 100);
std::cout << msg2 << std::endl;
std::cout << size << std::endl;
size = DAQmxGetErrorString(size, msg2, 100);
std::cout << msg2 << std::endl;
std::cout << size << std::endl;
size = DAQmxGetErrorString(error, msg, 0);
std::cout << size << std::endl;
size = DAQmxGetErrorString(error, NULL, 100);
std::cout << size << std::endl;
size = DAQmxGetErrorString(error, NULL, 0);
std::cout << size << std::endl;
delete [] msg;
return 0;
}
Which when run prints out:
Explanation could not be found for the requested status code.
Verify that the requested status cod
200026
Requested string could not fit into the given buffer. Only the first part of the
string was copied
200026
0
0
0
Those zeros should be the size of the character array to properly recieve the message, not 0.
