!! +var+ +file+
tit:checkdata
type:$type_var
alias:checkdatamodule
syntax:!checkdata
mean:This command is used to check whether datamodules required by\
  the present module are installed on the server. It returns "yes" if every\
  required datamodule is installed or if no datamodule is required. Otherwise\
  it returns the address of the first missing datamodule.\
  <p>\
  If your module depends on datamodules to run, declare them in the INDEX\
  file, then use this command to check the presence of the datamodules. If\
  the answer is "no", you can take actions to lock further access to your\
  module and/or show error messages.\
  </p>
