TAL Reference Manual

Glossary
Glossary—526371.001
Glossary-6
environment register.
environment register. A facility that contains information about the current process, such
as the current RP value and whether traps are enabled.
equivalenced variable. A declaration that associates an alternate identifier and description
with a location in a primary storage area.
expression. A sequence of operands and operators that, when evaluated, produces a
single value.
EXTDECS. A file, provided by the operating system, that contains external declarations for
system procedures. System procedures, for example, manage files, activate and
terminate programs, and monitor the operations of processes.
extended data segment. A segment that provides up to 127.5 megabytes of indirect data
storage. A process can have more than one extended data segment:
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The compiler allocates an extended data segment when you declare extended
indirect arrays or indirect structures.
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Your process can also allocate explicit extended data segments.
extended indirect addressing. Data access through an extended (32-bit) pointer.
extended pointer. A 32-bit simple pointer or structure pointer. An extended pointer can
contain a 32-bit byte address of any location in virtual memory.
extended stack. A data block named $EXTENDED#STACK that is created in the
automatic extended data segment by the compiler when you declare extended indirect
arrays and structures.
EXTENSIBLE procedure. A procedure that you declare using the EXTENSIBLE keyword; a
procedure to which you can add formal parameters without recompiling its callers; a
procedure for which the compiler considers all parameters to be optional, even if some
are required by your program. Contrast with VARIABLE procedure
external declarations file. A file that contains declarations for procedures declared in
other source files.
EXTERNAL procedure declaration. A procedure declaration that includes the EXTERNAL
keyword and no procedure body; a declaration that enables you to call a procedure
that is declared in another source file.
file ID. The last of the four parts of a file name.
file name. A fully qualified file ID. A file name contains four parts separated by periods:
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Node name (system name)
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Volume name
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Subvolume name