dfork.h(3)

📦

version 0.14 · 4 versions

0.14 · ubuntu noble, ubuntu questing (latest)
0.14 · ubuntu jammy
0.14 · ubuntu resolute, ubuntu stonking
0.14 · debian bookworm, debian trixie

🌸 dfork.h — NAME 🌸

okay so bestie, gather round 💖 dfork.h is the header that hands you a whole entire API for doing a daemonizing fork(). that's the whole vibe. it's giving "spawn a background process, but make it correct and make it slay" 👑

✨ SYNOPSIS ✨

#include <sys/types.h>

🎀 Macros

#define DAEMON_CLOSE_ALL_AVAILABLE 1 — this macro is defined to 1 iff daemon_close_all() and daemon_close_allv() are supported. literally the "do you have this feature" check 💅
#define DAEMON_UNBLOCK_SIGS_AVAILABLE 1 — defined to 1 iff daemon_unblock_sigs() and daemon_unblock_sigsv() are supported.
#define DAEMON_RESET_SIGS_AVAILABLE 1 — defined to 1 iff daemon_reset_sigs() and daemon_reset_sigsv() are supported.

🦋 Functions

pid_t daemon_fork (void) — does a daemonizing fork(). the main character of this whole header fr fr.
int daemon_retval_init (void) — allocate and initialize the resources that the daemon_retval_xxx() functions need.
void daemon_retval_done (void) — frees the resources that daemon_retval_init() allocated. cleanup era 🧹
int daemon_retval_wait (int timeout) — return the value the child sent via daemon_retval_send(), but only wait the specified number of seconds before it times out and returns 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 the ones you passed.
int daemon_close_allv (const int except_fds[]) — same as daemon_close_all but it takes an array of fds, terminated by -1.
int daemon_unblock_sigs (int except,...) — unblock all signals except the ones you passed.
int daemon_unblock_sigsv (const int except[]) — same as daemon_unblock_sigs() but it takes an array of signals, terminated by -1.
int daemon_reset_sigs (int except,...) — reset all signal handlers except the ones you passed.
int daemon_reset_sigsv (const int except[]) — same as daemon_reset_sigs() but it takes an array of signals, terminated by -1.

💜 Detailed Description

contains an API for doing a daemonizing fork(). yes that's the sentence, and yes it's iconic.

you may daemonize by calling daemon_fork(), a function similar to the plain fork(). and 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. that's the whole plot 🍓

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. no cap.

Since

0.11

`#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

`#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

🔥 Function Documentation

`int daemon_close_all (int except_fd, ...)`

close all file descriptors except the ones passed. the list needs to be terminated by -1. and heads up — FDs 0, 1, 2 will be kept open anyway, always, no matter what you say. they're not like other fds 💅

Since

0.11

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

`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 /, and the umask is set to 777. she's fully self-sufficient, she's moved out, she's got her own place 🏠✨

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. so like. check your errno, bestie 😭

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

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

`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. and listen — the resources allocated by daemon_retval_init() should be freed in both the parent and the daemon process. you can achieve that by using daemon_retval_wait() resp. daemon_retval_send(), or by using daemon_retval_done(). it's giving "two ways to leave the party, but you DO have to leave" 🙈

Examples

testd.c.

`int daemon_retval_init (void)`

allocate and initialize the resources required by the daemon_retval_xxx() functions. these functions let the child send a value to the parent after completing its initialisation. call this in the parent before forking. order matters, bestie 🎀

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 🚨 (like, the library reserves that value, so sending it is you breaking the contract). 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 — the timeout in seconds

Returns

the integer passed to 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. let them through, girl, except the ones you're specifically holding back 🦋

Since

0.13

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

👑 Author

generated automatically by Doxygen for libdaemon from the source code. the robot wrote it, I just gave it a personality 💖

and that's the whole page, bestie 🫶 this is dfork.h(3), part of libdaemon, Version 0.14, and it was generated by Doxygen for libdaemon straight from the source code. go forth and daemonize responsibly, mwah 💅✨🌸

📦 where this page comes from

ubuntu noble: libdaemon-doc 0.14-7.1ubuntu4
ubuntu questing: libdaemon-doc 0.14-7.1ubuntu4
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-10-14: a language model's rewrite of the original, under its terms

dfork.h(3)

🌸 dfork.h — NAME 🌸

✨ SYNOPSIS ✨

🎀 Macros

🦋 Functions

💜 Detailed Description

🌈 Macro Definition Documentation

#define DAEMON_CLOSE_ALL_AVAILABLE 1

Since

See also

#define DAEMON_RESET_SIGS_AVAILABLE 1

Since

See also

#define DAEMON_UNBLOCK_SIGS_AVAILABLE 1

Since

See also

🔥 Function Documentation

int daemon_close_all (int except_fd, ...)

Since

See also

Examples

int daemon_close_allv (const int except_fds[])

Since

See also

pid_t daemon_fork (void)

Returns

Examples

int daemon_reset_sigs (int except, ...)

Since

See also

Examples

int daemon_reset_sigsv (const int except[])

Since

See also

void daemon_retval_done (void)

Examples

int daemon_retval_init (void)

Returns

Examples

int daemon_retval_send (int s)

Parameters

Returns

Examples

int daemon_retval_wait (int timeout)

Parameters

Returns

Examples

int daemon_unblock_sigs (int except, ...)

Since

See also

Examples

int daemon_unblock_sigsv (const int except[])

Since

See also

👑 Author

`#define DAEMON_CLOSE_ALL_AVAILABLE 1`

`#define DAEMON_RESET_SIGS_AVAILABLE 1`

`#define DAEMON_UNBLOCK_SIGS_AVAILABLE 1`

`int daemon_close_all (int except_fd, ...)`

`int daemon_close_allv (const int except_fds[])`

`pid_t daemon_fork (void)`

`int daemon_reset_sigs (int except, ...)`

`int daemon_reset_sigsv (const int except[])`

`void daemon_retval_done (void)`

`int daemon_retval_init (void)`

`int daemon_retval_send (int s)`

`int daemon_retval_wait (int timeout)`

`int daemon_unblock_sigs (int except, ...)`

`int daemon_unblock_sigsv (const int except[])`