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Diffstat (limited to 'lib/libc/gen/ftok.3')
-rw-r--r-- | lib/libc/gen/ftok.3 | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/lib/libc/gen/ftok.3 b/lib/libc/gen/ftok.3 new file mode 100644 index 0000000..9b25bf2 --- /dev/null +++ b/lib/libc/gen/ftok.3 @@ -0,0 +1,88 @@ +.\" Copyright (c) 1994 SigmaSoft, Th. Lockert <tholo@sigmasoft.com> +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; +.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, +.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR +.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF +.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.\" $Id: ftok.3,v 1.1 1994/06/26 16:24:57 jtc Exp $ +.Dd June 24, 1994 +.Os +.Dt ftok 3 +.Sh NAME +.Nm ftok +.Nd create IPC indentifier from path name +.Sh SYNOPSIS +.Fd #include <sys/types.h> +.Fd #include <sys/ipc.h> +.Ft key_t +.Fn ftok "const char *path" "char id" ; +.Sh DESCRIPTION +.Bf -symbolic +This function is available from the compatibility library, libcompat. +.Ef +The +.Fn ftok +function attempts to create a unique key suitable for use with the +.Xr msgget 2 , +.Xr semget 2 +and +.Xr shmget 2 +functions given the +.Fa path +of an existing file and a user-selectable +.Fa id . +.Pp +The specified +.Fa path +must specify an existing file that is accessible to the calling process +or the call will fail. Also, note that links to files will return the +same key, given the same +.Fa id . +.Sh RETURN VALUES +The +.Fn ftok +function will return -1 if +.Fa path +does not exist or if it cannot be accessed by the calling process. +.Sh SEE ALSO +.Xr msgget 2 , +.Xr semget 2 , +.Xr shmget 2 +.Sh HISTORY +The +.Fn ftok +function originate with System V and is typically used by programs +that use the System V IPC routines. +.Sh AUTHOR +.Bl -tag +Thorsten Lockert <tholo@sigmasoft.com> +.El +.Sh BUGS +The returned key is computed based on the device and inode of the +specified +.Fa path +in combination with the given +.Fa id . +Thus is is quite possible for the routine to return duplicate keys +given that those fields are not 8- and 16-bit quantities like they +were on System V based systems where this library routine's ancestor +were originally created. |