So do I need to write the equivalent of that for every single network_ and buffer_ function that I've used? And is the : meant to be a : or a ;
Viewing post in Do ports not work the same when using GMLive?
You would need to write that for functions that do not work correctly as-is and return 0 instead of the intended value (it wasn’t until GMS2.3 that scripts with no return values would return a more meaningful undefined). The exact functions can be established by testing or by comparing existing wrappers in GMLAPI.gml to the manual.
: is a colon, which for GMLive indicates that a function is expected to return something.