PS TEXT FORMAT Reference Manual

Introduction to TFORM
3–36 11387 Tandem Computers Incorporated
Tips
Four read files and four write files are the maximum number of
auxiliary files that can be open at one time.
With any FILE OPEN command, if four files are already open for
reading or writing, TFORM issues an error message and ignores the
command.
If you fail to supply a FILE CLOSE command, TFORM closes all files
that are open when it terminates.
You can add a simple IF construct to your file that will check for any
FILE command errors. TFORM can tell you when you use an incorrect
FILE READ or FILE WRITE command and what GUARDIAN 90 file
system error code the FILE command assigns to the SYS_FILEERROR
variable.
After a FILE OPEN and a FILE READ (or FILE WRITE) command, add
these three command lines
\IF SYS_FILEERROR<>0
\ ERROR "I found an error; its code is \(sys_fileerror\)"
\ENDIF
4
3
2
1
1
TFORM checks if SYS_FILEERROR has a value other than 0
2
Text of error message you provide for TFORM to use if value <>0
is found
3
SYS_FILEERROR variable for TFORM to evaluate, giving you the
error code
4
Terminates the IF construct