COBOL Manual for TNS/E Programs (H06.08+, J06.03+)

Example 84 DISPLAY Statement
IF IO-STATUS = "23"
DISPLAY "I-O ERROR " IO-STATUS
" - NO RECORD FOR KEY = " INVOICE-NUMBER
END-IF
If INVOICE-NUMBER is 00246, the output from the code in Example 74 looks like this:
I-O ERROR 23 - NO RECORD FOR KEY = 00246
Usage Considerations:
• Differences in the OSS and Guardian Environments
In the OSS environment (but not in the Guardian environment), if a DISPLAY statement includes
mnemonic-name, it must be either the OSS pathname of a Guardian file or the name of an
OSS text file.
• Devices
The devices to which the DISPLAY statement can transmit data are terminals (including the
operator’s console), printers, processes (including spooler collectors), and entry-sequences
files. Once the DISPLAY device is assigned, the program cannot change it. The WRITE statement
is recommended for all but the smallest amounts of data.
• Specifying the Wrong Device
If you specify a device that cannot be used for DISPLAY output, the process displays a run-time
error message and the output on its home terminal. The error message includes this line:
Device assigned to ACCEPT or DISPLAY not a legal device
• Opening and Closing Devices
The display operation opens and closes the terminal or printer (but not a process) for each
DISPLAY statement. This prevents a COBOL program from locking out other users between
displays. Because a process is not prevented from accepting requests from other run units,
COBOL does not close a process after each display operation; instead, it waits until execution
of the run unit terminates.
• How Different Types of Values Are Displayed
Numeric values
A numeric value is displayed as a numeric literal, preceded by a minus sign if the value
is negative, and with a decimal point before any fractional digits. The number of digits
displayed is the number of digits defined for the sending item.
◦
A function that returns a floating-point value (such as NUMVAL or NUMVAL-C) is displayed
as if the value were described as PICTURE S9(18), with no decimal positions. For this
reason, do not reference such functions in DISPLAY statements. Instead, move the values
that such functions return to temporary variables that have decimal points in the appropriate
positions and display the temporary variables.
◦ Nonnumeric values
A nonnumeric value is displayed as a string of characters.
DISPLAY 313