Pipes and Command Pipes
InterSystems IRIS supports both standard pipes and command pipes (CPIPE). Standard pipes are used for relative short command strings, in which the command name and its arguments are less than 256 characters. Command pipes are used when the command string is 256 characters or more in length. In both cases, pipes can only be used on UNIX® and Windows systems.
Standard Pipe OPEN
The following is the OPEN command syntax for standard pipes:
OPEN program:(parameters):timeout
Because program is the first argument (the device argument), it must follow the OPEN command device name limitation of 256 characters.
If an OPEN command is issued for a standard pipe that is already open, the second OPEN is ignored. No error is issued.
Command Pipe OPEN
The following is the OPEN command syntax for command pipes:
OPEN cpipename:program:timeout
OPEN cpipename:(program:parameters:::closetimeout):timeout
The cpipename argument can take the value "|CPIPE|" if there is only command pipe open concurrently. To open multiple concurrent pipes, specify "|CPIPE|xxxxxx", where xxxxxx represents a user-specified unique identifier. This cpipename argument is the argument specified for subsequent USE and CLOSE commands.
Because program is the second argument, it is not limited to 256 characters. The maximum length of program is platform dependent.
If an OPEN command is issued for a command pipe that is already open, the second OPEN is ignored. No error is issued.
