The ZDEALLOCATE command releases a specified resource name or names previously reserved by the ZALLOCATE command. The ZDEALLOCATE command releases only the specified name(s) without releasing other names previously reserved with the ZALLOCATE or LOCK command.
The ZDEALLOCATE command provides compatibility with some other GT.M implementations. The M Development Committee choose to add the + and - delimiters to the LOCK command rather than adopt the ZALLOCATE and ZDEALLOCATE approach. Therefore, when a design requires an incremental lock mechanism, LOCK +/- has the advantage of being part of the M standard. LOCK +/- also has the advantage of working symmetrically when routines using LOCKs are nested.
The format of the ZDEALLOCATE command is:
The optional truth-valued expression immediately following the command is a command postconditional that controls whether or not GT.M executes the command
The nref argument specifies a name in the format of a GT.M name with or without subscripts and with or without a leading caret (^).
A ZDEALLOCATE with no argument releases all names currently reserved with ZALLOCATE by the process; in this case, at least two (2) spaces must follow the ZDEALLOCATE to separate it from the next command on the line.
ZDEALLOCATEing a named resource that is not currently owned by the process has no effect.
An indirection operator and an expression atom evaluating to a list of one or more ZDEALLOCATE arguments form a legal argument for a ZDEALLOCATE.
For examples of ZALLOCATE, refer to “Examples of ZALLOCATE”.