CM Modula-3: Runtime arguments

Runtime arguments

Command line arguments given to Modula-3 programs are divided in two groups. Runtime parameters are those that start with the characters @M3. They are reserved for the Modula-3 runtime and are accessible via the RTParams interface. The others are program arguments and are accessible via the Params interface.

The following runtime parameters are recognized today; others are simply ignored.

@M3nogc turns the garbage collector off.
@M3showheap=name activates the logging of heap allocation and garbage collection events. The program forks a process running the name program, and sends it these events as they occur. If "=name" is omitted, the showheap program is forked (it is part of the tools archive); this program displays the status of the heap pages.
@M3showthread=name activates the logging of thread switching events. The program forks a process running the name program, and sends it these events as they occur. If "=name" is omitted, the showthread program is forked (it is part of the tools archive); this program displays the status of the various threads.
@M3shownew=name activates the logging of per-type heap allocations. The program forks a process running the name program, and periodically sends it the number and sizes of recently allocated objects. If "=name" is omitted, the shownew program is forked (it is part of the tools archive); this program displays one of several bar graphs.
@M3update=X sets the interval between shownew updates to X seconds. X must be an integer.
@M3noincremental disables incremental garbage collection; uses stop-and-copy instead.
@M3nogenerational disables generational garbage collection.
@M3novm disables the use of VM protection by the garbage collector. On some platforms, @M3novm is essential for debugging. @M3novm implies @M3noincremental and @M3nogenerational.
@M3paranoidgc checks the heap for sanity after each collection.
@M3stackdump causes checked runtime errors to produce a stack dump on stderr. On systems with stack walkers (DS3100 and ALPHA_OSF) the dump includes exception and procedure frames. On other systems only the exception frames are dumped.