Error handling

You should always check the status attribute of the dmpresource after every dmpinit call, to see if it succeeded or not. This status will be DMP_OK on success, DMP_NOT_FOUND if the resource you requested did not exist, DMP_ACCESS_DENIED if you don't have access to the resource you requested; any other values indicate internal errors. When the status is not DMP_OK, you can find a human-readable error message in the lasterror attribute. For example:

declarations
  myservice: dmpresource
end-declarations
dmpinitwebservice(myservice,'processLoanApps')
if myservice.status=DMP_OK then
  writeln('Service found OK')
elif myservice.status=DMP_NOT_FOUND then
  writeln('Service not found')
else then
  writeln('Failed to find service due to error:', myservice.lasterror)
end-if

httpStatusCode := dmphttppost(myservice,'','request.json','result.json')
if httpStatusCode<>200 then
  writeln('Error returned by webservice: ',httpStatusCode)
  exit(1)
end-if