IOUNIT - find the B I/O unit for a file variable.

Usage:

unit := iounit( filevar );

Where:

filevar: is an open file variable.
unit: is the B unit number corresponding to "filevar".

Description:

There are a number of useful I/O related functions in the B library. Some of these are applicable to the Pascal user. However, to use them you must know the B "unit number". IOUNIT returns the B unit number associated with an open Pascal file variable. If "filevar" is not open, the program will be aborted.

IOUNIT is predeclared by the compiler so that it can take a file variable of any type.