HP Pascal/iX Reference Manual (31502-90022)

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Halt Procedure.
The halt procedure causes an abnormal termination of a program.
Heap Procedures.
The procedure mark saves the allocation state of the heap. The procedure
release restores the allocation state of the heap to a state previously
marked. This has the effect of deallocating all storage allocated by the
procedure new since the time mark was called.
Identifiers.
The underscore character (_) can appear in identifiers, but not as the
first character.
File Input/Output.
A file can be opened for direct access with the procedure open . Direct
access files have a maximum number of components indicated by the
function maxpos and have a current number of written components,
indicated by the function lastpos . The procedure seek places the current
position of a direct access file at a specified component. Data can be
read from a direct access file or written to it with the procedures
readdir or writedir that are combinations of seek and the standard
procedures read or write . A textfile cannot be used as a direct access
file.
A file can be opened in the "write-only" state without altering its
contents by using the procedure append . The current position is set to
the end of the file.
Any file can be explicitly closed with the procedure close .
To permit interactive input, the system defines the primitive file
operation get as "deferred get." Refer to get in Chapter 10 for more
information.
The procedure read accepts any ordinal type as input from text files.
Therefore, it is possible to read a Boolean or enumerated value from a
text file. It is also possible to read a value that is of type PAC or
string.
The procedure write writes expressions to a text file. Any ordinal type
can be a parameter. An enumerated constant can be written directly to a
text file. Write also writes expressions of type string or PAC.
The function position returns the index of the current position for any
file that is not a textfile.
The routines page , overprint , prompt , and linepos operate on textfiles.
The following lists what each routine does:
* Linepos returns the integer number of characters that the program
has read from or written to a textfile since the last end-of-line
marker.
* Page causes a page eject when a text file is printed.
* Overprint causes the printer to perform a carriage return without
a line feed, effectively overprinting a line.