NAME

       dfork.h - Contains an API for doing a daemonizing fork().

SYNOPSIS

       #include <sys/types.h>

   Macros
       #define DAEMON_CLOSE_ALL_AVAILABLE   1
           This variable is defined to 1 iff daemon_close_all() and daemon_close_allv() are
           supported.
       #define DAEMON_UNBLOCK_SIGS_AVAILABLE   1
           This variable is defined to 1 iff daemon_unblock_sigs() and daemon_unblock_sigsv() are
           supported.
       #define DAEMON_RESET_SIGS_AVAILABLE   1
           This variable is defined to 1 iff daemon_reset_sigs() and daemon_reset_sigsv() are
           supported.

   Functions
       pid_t daemon_fork (void)
           Does a daemonizing fork().
       int daemon_retval_init (void)
           Allocate and initialize resources required by the daemon_retval_xxx() functions.
       void daemon_retval_done (void)
           Frees the resources allocated by daemon_retval_init().
       int daemon_retval_wait (int timeout)
           Return the value sent by the child via the daemon_retval_send() function, but wait
           only the specified number of seconds before timing out and returning a negative
           number.
       int daemon_retval_send (int s)
           Send the specified integer to the parent process.
       int daemon_close_all (int except_fd,...)
           Close all file descriptors except those passed.
       int daemon_close_allv (const int except_fds[])
           Same as daemon_close_all but takes an array of fds, terminated by -1.
       int daemon_unblock_sigs (int except,...)
           Unblock all signals except those passed.
       int daemon_unblock_sigsv (const int except[])
           Same as daemon_unblock_sigs() but takes an array of signals, terminated by -1.
       int daemon_reset_sigs (int except,...)
           Reset all signal handlers except those passed.
       int daemon_reset_sigsv (const int except[])
           Same as daemon_reset_sigs() but takes an array of signals, terminated by -1.

Detailed Description

       Contains an API for doing a daemonizing fork().

       You may daemonize by calling daemon_fork(), a function similar to the plain fork(). If you
       want to return a return value of the initialization procedure of the child from the
       parent, you may use the daemon_retval_xxx() functions.

       Definition in file dfork.h.

Macro Definition Documentation

   #define DAEMON_CLOSE_ALL_AVAILABLE   1
       This variable is defined to 1 iff daemon_close_all() and daemon_close_allv() are
       supported.

       Since
           0.11

       See also
           daemon_close_all(), daemon_close_allv()

       Definition at line 106 of file dfork.h.

   #define DAEMON_RESET_SIGS_AVAILABLE   1
       This variable is defined to 1 iff daemon_reset_sigs() and daemon_reset_sigsv() are
       supported.

       Since
           0.13

       See also
           daemon_reset_sigs(), daemon_reset_sigsv()

       Definition at line 142 of file dfork.h.

   #define DAEMON_UNBLOCK_SIGS_AVAILABLE   1
       This variable is defined to 1 iff daemon_unblock_sigs() and daemon_unblock_sigsv() are
       supported.

       Since
           0.13

       See also
           daemon_unblock_sigs(), daemon_unblock_sigsv()

       Definition at line 124 of file dfork.h.

Function Documentation

   int daemon_close_all (int except_fd,  ...)
       Close all file descriptors except those passed. List needs to be terminated by -1. FDs 0,
       1, 2 will be kept open anyway.

       Since
           0.11

       See also
           DAEMON_CLOSE_ALL_AVAILABLE

       Examples
           testd.c.

   int daemon_close_allv (const int except_fds[])
       Same as daemon_close_all but takes an array of fds, terminated by -1.

       Since
           0.11

       See also
           DAEMON_CLOSE_ALL_AVAILABLE

   pid_t daemon_fork (void)
       Does a daemonizing fork(). For the new daemon process STDIN, STDOUT, STDERR are connected
       to /dev/null, the process is a session leader, the current directory is changed to /, the
       umask is set to 777.

       Returns
           On success, the PID of the child process is returned in the parent's thread of
           execution, and a 0 is returned in the child's thread of execution. On failure, -1 will
           be returned in the parent's context, no child process will be created, and errno will
           be set appropriately.

       Examples
           testd.c.

   int daemon_reset_sigs (int except,  ...)
       Reset all signal handlers except those passed. List needs to be terminated by -1.

       Since
           0.13

       See also
           DAEMON_RESET_SIGS_AVAILABLE

       Examples
           testd.c.

   int daemon_reset_sigsv (const int except[])
       Same as daemon_reset_sigs() but takes an array of signals, terminated by -1.

       Since
           0.13

       See also
           DAEMON_RESET_SIGS_AVAILABLE

   void daemon_retval_done (void)
       Frees the resources allocated by daemon_retval_init(). This should be called if neither
       daemon_retval_wait() nor daemon_retval_send() is called in the current process. The
       resources allocated by daemon_retval_init() should be freed in both parent and daemon
       process. This may be achieved by using daemon_retval_wait() resp. daemon_retval_send(), or
       by using daemon_retval_done().

       Examples
           testd.c.

   int daemon_retval_init (void)
       Allocate and initialize resources required by the daemon_retval_xxx() functions. These
       functions allow the child to send a value to the parent after completing its
       initialisation. Call this in the parent before forking.

       Returns
           zero on success, nonzero on failure.

       Examples
           testd.c.

   int daemon_retval_send (int s)
       Send the specified integer to the parent process. Do not send -1 because this signifies a
       library error. Should be called just once from the daemon process only. A subsequent call
       to daemon_retval_done() in the daemon is ignored.

       Parameters
           s The integer to pass to daemon_retval_wait() in the parent process

       Returns
           Zero on success, nonzero on failure.

       Examples
           testd.c.

   int daemon_retval_wait (int timeout)
       Return the value sent by the child via the daemon_retval_send() function, but wait only
       the specified number of seconds before timing out and returning a negative number. Should
       be called just once from the parent process only. A subsequent call to
       daemon_retval_done() in the parent is ignored.

       Parameters
           timeout Thetimeout in seconds

       Returns
           The integer passed daemon_retval_send() in the daemon process, or -1 on failure.

       Examples
           testd.c.

   int daemon_unblock_sigs (int except,  ...)
       Unblock all signals except those passed. List needs to be terminated by -1.

       Since
           0.13

       See also
           DAEMON_UNBLOCK_SIGS_AVAILABLE

       Examples
           testd.c.

   int daemon_unblock_sigsv (const int except[])
       Same as daemon_unblock_sigs() but takes an array of signals, terminated by -1.

       Since
           0.13

       See also
           DAEMON_UNBLOCK_SIGS_AVAILABLE

Author

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