NAME

ftok - calculate System V IPC keys using the ftok(3) library function

SYNOPSIS

ftok [ OPTION ] FILENAME ID

DESCRIPTION

Calculate a System V IPC key from the given FILENAME and ID using the ftok(3) library function, and print the result to standard output. If not otherwise specified, the key is printed in hexadecimal format, with a 0x prefix.

FILENAME: The name of an existing file. This does not need to be a regular file, directories and special files should work, too.
ID: A number between (including) 0 and 255.

If shmcat has been compiled without getopt_long(3) support, only the short, one character OPTIONs can be used. Otherwise the long ones are also available.

OPTIONS

-d, --decimal: Print the result in decimal format, without any prefix.
-h, -?, --help: Display usage information and quit without further action.
-o, --octal: Print the result in octal format and use a leading zero (0) as prefix.
-V, --version: Show version information and quit.

EXIT CODES

0: No errors, the key was calculated and printed.
1: There was an error calculating or printing the key.
10: Wrong usage of the program.

CAVEATS

The ftok(1) utility has the same limitations as the ftok(3) library function. That means, there is no guarantee that the resulting key is unique.

On Linux, passing 0 as the ID (second parameter) to the ftok(3) function seems to work, but this behavior is unspecified. The ftok(1) tool accepts 0 as an ID and leaves it to the library implementation on what to do with that.

AUTHOR

Stefan Gast