libtools/daemonize_8h_source.html

 #ifndef __TOOLS_DAEMONIZE_H
 #define __TOOLS_DAEMONIZE_H

 #include <unistd.h>

 pid_t daemonize(const char *path, char *const argv[], int nochdir, int noclose);

 int pidlock_set(const char *path);

 pid_t pidlock_get(const char *path);

 #endif /* __TOOLS_DAEMONIZE_H */
daemonize
pid_t daemonize(const char *path, char *const argv[], int nochdir, int noclose)
run program as daemon

pidlock_set
int pidlock_set(const char *path)
try to save pid of calling process to file

pidlock_get
pid_t pidlock_get(const char *path)
read pid from file and verify it