DXL ignoring the error if an attribute doesn't exist in a module

Question

I am writing some DXL for use as a DXL column that for each object in a module, looks at the in-links and returns the link name. Then if the link name starts with "verif", it will get the object text from an attribute "TestResultFloating" in the linked module and show it in the current module, in the DXL column.

The problem I will have when I use this on the whole database (currently I am just using a sandbox) is that some of the modules linked through the "verif" link module will not contain the "TestResultFloating" attribute. For these I would like to oppress the 'unknown Object attribute (TestResultFloating)' error and instead display something like N/A for that Object in the current module.

Below is my code that currently works as long as the "TestResultFloating" attribute is present in the linked module, but will throw the error if the attribute is not present.

ModName_ mSrc
Object o = current
Object nObject
Object oSrc, oDest
LinkRef lr = null
Link l = null
string linkname = ""
string attrbName = "TestResultFloating"

  for mSrc in (obj <- "*") do {

    if (!open(mSrc)) {
      read(fullName(mSrc), true)
    }
  }

  for l in (obj <- "*") do {

    oSrc = source(l)
    linkname = name(module(l))
    string linkmodname = upper(linkname[0:4])

    if(linkmodname == "VERIF") {
      string objText = oSrc."TestResultFloating"
      display(objText)
      }
  }

I tried one way of doing it which I got from the dxl reference manual which was to check whether the attribute exists and then do the operation. This is what I added but it doesn't seem to work, I still get the same error "unknown Object attribute (TestResultFloating)" What I tried is shown below:

if(linkmodname == "VERIF") {
      if(exists attribute "TestResultFloating"){
        string objText = oSrc."TestResultFloating"
        display(objText)
    }
      else {
        display("N/A")
      }
    }

Please also note that i'm very new to DOORS and DXL so if I am doing something drastically wrong or I am asking a simple question please forgive me.

Answer 1

There is a utility function called string probeAttr_(Object o, string attrName) that can be used for getting an attribute value if you are not sure whether the attribute is readable or whether it even exists.
This function and a lot of similar functions tailored for different circumstances can be found in the file "c:\Program Files\IBM\Rational\DOORS\9.6\lib\dxl\utils\attrutil.inc"