Segmentation fault when Record Processing in StreamDevice

[Donny Domagoj Cosic via Tech-talk <tech-talk@aps.anl.gov>]

Hi,

I have an IOC to read data from a radiation monitor that continuously 
send out data, however every so often the device sends out a header 
which is formatted differently and this is causing a Segmentation fault 
and crashing the IOC.

The output from the probe:

??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
<\f>User File Number:          1<\r>
<\r>
  Date     Time    M.Time       A           B    <\r>
                    min       uSv/h       uSv/h  <\r>
--------------------------------------------------<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>
??/??/?? ??:??:??     0.1     0.19(1)     0.15(1)<\r>


My DB file:

record (ai, "RAD:P10Probe1")
{
	field(DTYP, "stream")
	field(INP, "@rad.proto getProbe1(RAD:message) PORT10")
	field(SCAN, "I/O Intr")
	field(HIHI, "10.0")
	field(HIGH, "1.0")
	field(HHSV, "MAJOR")
	field(HSV, "MINOR")
	field(LOPR, "0")
	field(EGU, "uS/hr")
}

record (ai, "RAD:P10Probe2")
{
	field(DTYP, "stream")
	field(INP, "@rad.proto getProbe2(RAD:message) PORT10")
	field(SCAN, "I/O Intr")
	field(HIHI, "10.0")
	field(HIGH, "1.0")
	field(HHSV, "MAJOR")
	field(HSV, "MINOR")
	field(LOPR, "0")
	field(EGU, "uS/hr")
}

My proto file:

Terminator = CR;

getProbe1
{
  in "%*8s\_%*8s\_%*f\_%f(%*d)\_%*f(%*d)";
  ExtraInput = Ignore;
  @mismatch
  {
    in "%(\$1)52c";
  }

}

getProbe2
{
  in "%*8s\_%*8s\_%*f\_%*f(%*d)\_%f(%*d)";
  ExtraInput = Ignore;
  @mismatch
  {
    in "%(\$1)52c";
  }

}

I noticed that when the header is received, the mismatch exception 
handler is not triggered, but this might because the SCAN field is set 
to "I/O Intr" as the data rate depends on the dose measured at the 
probe. Why would this reading error cause a Segmentation Error and crash 
the IOC? Is there any other way read the string from the probe?

Thank you in advance for you time,

Regards,
Donny

--
Donny Domagoj Cosic
 Institut Ruđer Bošković, Bijenička cesta 54, 10000 Zagreb, Croatia