A GT.M programmer can execute an M routine from DCL using the VMS RUN utility or interactively, using the M commands from Direct Mode.
The run-time system executes compile-as-written code as long as it does not encounter the compile-time errors. If it detects an error, the run-time system suspends execution of a routine immediately and transfers control to Direct Mode or to a user-written error routine.
The VMS INSTALL utility can install an M image. Installing images as shareable allows multiple users to access the image as a single copy. This approach eliminates the use of a separate copy of the image for each user, allowing a more efficient use of physical memory and of the disk channel.
To run GT.M routines in batch mode, use the DCL SUBMIT command and an appropriate command file.
The run-time system utilizes a GT.M facility called ZLINK to link in an M routine. When a program or a Direct Mode command refers to an M routine that is not part of the current process, GT.M automatically uses the ZLINK facility and attempts to link the referenced routine (auto-ZLINK). The ZLINK facility also determines whether recompilation of the routine is necessary. When compiling as a result of a ZLINK, GT.M typically ignores errors in the source code.
The run-time system also provides incremental linking. The ZLINK command adds an M routine to the current image. This feature facilitates the addition of code modifications during a debugging session. The GT.M programmer can also use the feature to add patches and generated code to a running M process.