The dtw_initialize() interface function performs any special initialization that the language environment requires, such as connecting to a database or allocating variables. This interface function is called once and is optional.
Net.Data calls a language environment's dtw_initialize() interface function only once per macro, the first time Net.Data calls a FUNCTION block referencing that language environment. Subsequent references to the language environment bypass the call to the dtw_initialize() interface function.
This interface function does not affect message block processing. A positive or zero return code means that processing continues; a negative return code means that processing does not continue. If the return code is non-zero and there is a default message defined in the default_error_message field, the default message is issued; if there is no default message, Net.Data issues an error message.