Extensions For Additional Capability

For ways to adjust some process operating characteristics, see the command description “View”. For ways to get information about certain process operating characteristics, see the function description “$View()”.

In GT.M, support of environment specification for global names and resource names is possible. It is possible to excercise user code to customize interpretation of the environment specification. See Chapter5: “General Language Features of M” for details.

The following table summarizes GT.M extensions that increase general capability.

GT.M Extensions for Additional Capability
EXTENSION	EXPLANATION
View	Modifies the environment.
ZAllocate*	Facilitates incremental locking by locking a name without unlocking previously locked names.
ZDeallocate*	Unlocks one or more names without necessarily unlocking other names.
ZHelp	Provides access to on-line help.
ZWIthdraw	“Kills” data in a node without affecting the node’s descendants.
$Order()	Enhanced to return the next unsubscripted variable in collating sequence from the current environment. Name-level $ORDER() always returns an empty string when used with extended references.
$View()	Examines the GT.M environment.
$ZCStatus	Returns the status from the last compile.
$ZDate()	Converts a date and/or time in $HOROLOG format into formatted text, using a user-specified format string.
$ZPrevious()**	Returns the previous element in a collating sequence, at the current level of a local or global array.
$ZA,$ZB, $ZEOF	Return device dependent I/O status information.
$ZCOmpile	Maintains the compiler qualifiers to be used on automatic compilation.
$ZBIT functions	A series of functions beginning with the characters $ZBIT that allow manipulation of bits.
$ZGBLdir	Maintains the name of the current global directory; may be set to switch this process to a new database.
$ZIO	Contains translated name of current I/O device.
$ZINTerrupt	Specifies the code to be XECUTE’d when an interrupt is processed.
$ZKEY	SD: Returns current position in the sequential file based on last read.
$ZMAXTPTIme	Contains a value establishing the time duration GT.M should wait for the completion of all activities fenced by the current transaction’s outermost TSTART/TCOMMIT pair.
$ZROutines	Maintains the list of directories to search during look-ups of object and source files.
$ZSYstem	Returns the status code for the last subprocess invoked with the ZSYSTEM command.
$ZVERsion	Contains a designation of the current version name, level, and operating system.

*The ZALLOCATE and ZDEALLOCATE commands are provided for compatibility with other M systems. However, FIS recommends use of the standard LOCK command, which provides an incremental locking facility. The incremental lock provides both flexibility and greater compatibility with the M language standard.

**The $ZPREVIOUS function is provided for compatibility with previous versions of GT.M and other M systems. However, FIS recommends use of the standard two-argument form for the $ORDER function.