cRIO FRC_RobotTask error

[ss9090]

Hey guys. I don't have much time before my competition and I just got this error from the NetConsole;

0x28bffe8 (FRC_RobotTask): task 0x28bffe8 has had a failure and has stopped.

A search brings up no hits. Does anybody have any idea about what causes this task error and what I can do to solve this?

Will post code if necessary.
Quick replies would be lovely.

EDIT:
Got rid of my Initial error by fixing up my pointers, however I now get a new error upon clicking 'Enable' on the driver station:

0x28c00e0 (FRC_RobotTask): task 0x28c00e0 has had a failure and has stopped.
0x28c00e0 (FRC_RobotTask): fatal kernel task-level exception!

Again, help is much appreciated.

[Bharat Nain]

I saw an issue in Orlando where we were trying to gather input from the Analog Input on the DS Software. Sometimes, it returned a null and caused a null-pointer exception. I can't say if that is your issue but it is possible. Thanks to Andrew Schreiber for helping me track that bug down.

[ss9090]

Thanks Bharat. I'm currently going through looking for a similar issue. Figured it must be a an improper pointer assignment, so I'm scouring through the lines hehe. Glad to know I'm on the right track.

[bob.wolff68]

I agree - most likely the use of a null pointer. As a general rule of C/C++ programming, this is a MUST -- check all pointers before using them. **ALSO** if you 'delete' a pointer, set that pointer to NULL afterwards as well. The programming is a little more 'verbose', but it is SAFER. Crashing in a real-time robot is the PITS.

For instance: (Writing a sample that should be rather 'real' but is from memory so may come with issues...this is intended to show the use of pointer checking -- not syntax and running code)


ColorImage* pImage;
pImage = NULL;
AxisCamera& cam=AxisCamera::GetInstance();
BinaryImage* pBin;
pBin = NULL;

while(IsOperatorControl())
{
if (cam.IsFreshImage())
{
pImage = cam.GetImage();
if (pImage)
{
pBin = pImage->ThresholdHSL(x,y,z,zz,p,d,NULL);
if (pBin)
{
// Do something using pBin like particle report ...
}
else
printf("ERROR: ThresholdHSL() failed.\n");
}
else
printf("ERROR: GetImage() failed.\n");

// Done with the image -- must dispose of it.
// But *SHOULD* also reset it to NULL so it doesn't get used accidentally.
if (pImage)
{
delete pImage;
pImage = NULL;
}

// Done with the image -- must dispose of it.
// But *SHOULD* also reset it to NULL so it doesn't get used accidentally.
if (pBin)
{
delete pBin;
pBin = NULL;
}
}
}