HP PCL/PJL reference - Printer Job Language Technical Reference Manual

EN PJL Command Syntax and Format 2-9
Processing Invalid Commands
There are two general types of invalid commands: those commands
with syntax errors, and those that have syntax or semantic warnings.
Each type is handled differently.
• Syntax errors cause the printer to ignore the entire PJL
command, and include errors such as unrecognized
commands and command modifiers, strings missing closing
double-quotes, numeric values missing digits before the
decimal point, and numeric values encountered when
alphanumeric values are expected. When the printer receives
commands with syntax errors, it ignores the entire command.
For example, the value portion of the JOB command's NAME
option is a string and requires double quotes around the value
(as shown below). In the second example below, the JOB
command is ignored since the string (April Paychecks)
contains the opening but not the required closing quotes.
Valid command:
@PJL JOB NAME = "April Paychecks" <LF>
Invalid command:
@PJL JOB NAME = "April Paychecks <LF>
• Syntax warnings and semantic warnings are issued for
commands such as those having unsupported options, values
that are out of range, values that are the wrong type or
missing, or values that are included when none are allowed.
When the printer receives commands with syntax or semantic
warnings, it executes as much of the command as possible,
but the portion of the command containing the warning is
ignored.
• For example, in the following two sample PJL commands,
START is a valid option for the JOB command, but FINISH is
not a valid option (the END option should be used). The
START option is executed, but the FINISH option is ignored.
Valid command:
@PJL JOB START = 1 <LF>
Invalid command:
@PJL JOB START = 1 FINISH = HOME <LF>