newlib/winsup/cygwin/ipc.cc

40 lines
908 B
C++

/* ipc.cc: Single unix specification IPC interface for Cygwin
Copyright 2001 Red Hat, Inc.
Originally written by Robert Collins <robert.collins@hotmail.com>
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include <sys/ipc.h>
#include <sys/stat.h>
extern "C"
{
/* Notes: we return a valid key even if id's low order 8 bits are 0. */
key_t
ftok(const char *path, int id)
{
struct stat statbuf;
if (stat(path, &statbuf))
{
/* stat set the appropriate errno for us */
return (key_t) -1;
}
/* dev_t is short for cygwin
* ino_t is long for cygwin
* and we need 8 bits for the id.
* thus key_t is long long.
*/
return ((long long) statbuf.st_dev << (5*8)) | (statbuf.st_ino << (8) ) | (id & 0x00ff);
}
}