Hello,
How can I lock a file for a specified period of time (10 seconds) using the C language in Ubuntu Linux ?
+3
A:
It works like this:
#include <io.h>
#include <sys/file.h>
...
int f = open ("filename", O_RDONLY);
if (f < 0)
error();
if (flock (f, LOCK_EX))
error();
sleep (10);
if (flock (f, LOCK_UN))
error();
...
wallyk
2010-01-13 17:40:24
Keep in mind that these are not mandatory locks they're advisory locks - meaning everyone that uses the file need to flock it too. If they don't they're free to manipulate the file.
nos
2010-01-13 17:47:59
+1
A:
Use fcntl(2) to lock the file, then use alarm(2) to call your SIGALRM handler which will then unlock it.
Ignacio Vazquez-Abrams
2010-01-13 17:40:25
Hrm. `signal(7)` says no. `fcntl(2)` should be fine though.
Ignacio Vazquez-Abrams
2010-01-13 20:34:25