Name

px − Pascal code executor

Syntax

px [obj[argument...]]

Description

The px command interprets the abstract machine code generated by pi. The first argument is the file to be interpreted, and defaults to obj; remaining arguments are available to the Pascal program using the built-ins argv and argc.  The px command is also invoked by pix when running ‘load and go’.

If the program terminates abnormally an error message and a control flow backtrace are printed.  The number of statements executed and total execution time are printed after normal termination.  The p option of pi suppresses all of this except the message indicating the cause of abnormal termination.

Restrictions

Post-mortem traceback is not limited; infinite recursion leads to almost infinite traceback. 

Diagnostics

Most run-time error messages are self-explanatory.  Some of the more unusual ones are:

Reference to an inactive file
A file other than input or output was used before a call to reset or rewrite. 

Statement count limit exceeded
The limit of 500,000 executed statements (which prevents excessive looping or recursion) has been exceeded.

Bad data found on integer read

Bad data found on real read
Usually, non-numeric input was found for a number. For reals, Pascal requires digits before and after the decimal point so that numbers like ‘.1’ or ‘21.’ evoke the second diagnostic.

panic: Some message
Indicates a internal inconsistency detected in px probably due to a Pascal system bug.

Files

objdefault object file
pmon.outprofile data file

See Also

pi(1), pix(1)
"Berkeley Pascal User’s Manual," ULTRIX Supplementary Documents, Vol. II:Programmer