Paul Brown wrote:
> I am just about fnished writing a daemon, and would like to know how i
> can make the program fork into
> the background automatically..
The attached program contains suitable startup code for a daemon. You
only asked for step 1, but steps 2-5 are generally considered
necessary.
--
Glynn Clements <[EMAIL PROTECTED]>
#include <stdio.h> /* for perror */
#include <unistd.h> /* for fork, setsid, chdir, sysconf, close */
#include <sys/stat.h> /* for umask */
int main(void)
{
int n, i;
/* step 1: fork() a child process and exit */
switch (fork())
{
case -1: /* error */
perror("fork");
return 1;
case 0: /* child */
break;
default: /* parent*/
return 0;
}
/* step 2: establish a new session */
if (setsid() < 0)
{
perror("setsid");
return 1;
}
/* step 3: set the cwd */
if (chdir("/") < 0)
{
perror("chdir");
return 1;
}
/* step 4: reset the umask */
umask(0);
/* step 5: close open descriptors */
n = sysconf(_SC_OPEN_MAX);
if (n < 0)
n = 256;
for (i = 0; i < n; i++)
if (close(i) < 0)
perror("close");
/* everything else goes here */
return 0;
}
