When the logical name GTM$ROUTINES is defined, GT.M initializes $ZROUTINES to the value of GTM$ROUTINES. Otherwise, GT.M initializes $ZROUTINES to null. When $ZROUTINES is null, GT.M attempts to locate all source and object files in the process current default directory. $ZROUTINES="" is equivalent to $ZROUTINES="[]".

Commands or functions such as DO, GOTO, ZGOTO, ZBREAK, ZPRINT, and $TEXT may auto-ZLINK and thereby indirectly use $ZROUTINES. If their argument does not specify a directory, ZEDIT and explicit ZLINK use $ZROUTINES. ZPRINT and $TEXT use $ZROUTINES to locate a source file if GT.M cannot find the source file pointed to by the object file. For more information on ZLINK and auto-ZLINK, refer to the "Program Development Cycle" and "Commands" chapters in GT.M Programmer's Guide.

$ZROUTINES is a read-write Intrinsic Special Variable, which M can also SET the value. A $ZROUTINES value must have the form of a list of RMS directory and/or file-specifications delimited by commas (,).