Checking for the existence of a process

checkpid

Check for existence of a process

SYNTAX

checkpid process_number

Checks for the existence of the specified process and sets sys.Errno, the Sculptor system variable that stores system error numbers. This command is only relevant to UNIX systems. Under other operating systems it is ignored.

process_number

The number of the process to be checked. May be a constant or an expression.

If the process being checked for exists and has the same real or effective user-id as the calling process (the run time interpreter sagewc | srepwc), sys.Errno is set to zero. If the process does not exist, sys.Errno is set to the UNIX error code ESRCH (usually 3). If the process exists but has a different real or effective user-id to the calling process, sys.Errno is set to the UNIX error code EPERM (usually 1).

This command is provided for use by the Sculptor transaction recovery program, and is intended for experienced UNIX users only. Further information may be derived from the UNIX manual.

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EXAMPLE

checkpid tmp.ProcNo