Hi Ulli, On Dec 12 13:00, Ulli Horlacher wrote: > I need to store some data (a few kB) non-persistant. > On a real UNIX I would use /var/run, because after a shutdown all its > content is lost. > But on cygwin /var/run is stored on disk. > > I cannot use an environment variable, because different processes need to > read/write the data. > > /proc is non-persistant (in respect to a reboot), but It is not a generic > storage place. > > What can I use with cygwin instead? > > Installing third party software is not an option, it must work with a > standard Windows (and cygwin).
Cygwin is just a user space DLL, it's not an OS. Creating RAM disk-like
storage is the job of the OS or an OS driver. Unfortunately, there's no
onboard RAM disk driver in Windows, just zillions of third-party solutions.
I see two options:
- Use XSI shared memory, as outlined in this thread already, or
- If you have the executables under source control, you can use
an O_TMPFILE on /dev/shm, and fork the worker process from there,
i.e.
fd = open ("/dev/shm", O_TMPFILE | O_RDWR, S_IRUSR | S_IWUSR);
if (fd >= 0)
{
write (fd, your_key, strlen (your_key));
switch (fork ())
{
case 0: /* child */
/* Use fd as you see fit */
break;
case -1: /* error */
default: /* parent */
close (fd);
wait (&status);
break;
}
}
Corinna
--
Corinna Vinschen
Cygwin Maintainer
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