Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
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Marco Casaroli 9b787d42b2 sched/arch/libc: make task_fork() optional
task_fork() is a NuttX extension, not POSIX, and a configuration that does
not call it has no reason to carry it.  Add CONFIG_TASK_FORK to leave it out.

It depends on ARCH_HAVE_TASK_FORK and defaults to y, so it is enabled exactly
where fork() existed before the split and no configuration loses the primitive
by upgrading.  ARCH_HAVE_TASK_FORK keeps its meaning -- the architecture *can*
clone the calling task -- and the new symbol says whether this build wants it.
Everything that provides task_fork() moves to the new symbol:  the declaration
in sched.h, up_task_fork() in arch.h, the two .csv entries that generate the
system call stub and proxy, the syscall_lookup.h table entry, the architecture
entry points, and the build rules for the files that hold them.

FORK_IS_TASK_FORK now depends on TASK_FORK rather than ARCH_HAVE_TASK_FORK.
Aliasing fork() to a task_fork() that was not built would not link.

vfork() and fork() are untouched; each is still selected on its own, and
task_fork.c, lib_fork.c and the architecture's fork file are still built when
any one of the three is present.

Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>

Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-30 11:45:24 +02:00
.github build(deps): bump actions/setup-python from 6 to 7 2026-07-27 13:34:36 -04:00
arch sched/arch/libc: make task_fork() optional 2026-07-30 11:45:24 +02:00
audio tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
binfmt tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
boards boards/risc-v/esp32c6: Add SW LP Mailbox board support 2026-07-29 09:53:59 +08:00
cmake cmake: Omit default priority ELF symbol. 2026-07-27 14:30:42 +08:00
crypto tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
Documentation sched/arch/libc: make task_fork() optional 2026-07-30 11:45:24 +02:00
drivers drivers/syslog: fix syslog_write() returning -EIO on every write 2026-07-29 07:57:29 +02:00
dummy build: add initial cmake build system 2023-07-08 13:50:48 +08:00
fs tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
graphics tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
include sched/arch/libc: make task_fork() optional 2026-07-30 11:45:24 +02:00
libs sched/arch/libc: make task_fork() optional 2026-07-30 11:45:24 +02:00
mm tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
net tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
openamp tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
pass1 tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
sched sched/arch/libc: make task_fork() optional 2026-07-30 11:45:24 +02:00
syscall sched/arch/libc: make task_fork() optional 2026-07-30 11:45:24 +02:00
tools tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
video tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
wireless tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines arch/arm: Reserve r10 via ARCHCFLAGS and hoist the PIC module flags. 2026-07-24 23:09:08 +08:00
.codespellrc arch/arm/rp23xx: Add hardware TRNG driver for /dev/random. 2026-07-25 15:06:56 +08:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore git: Specify multiple build directories in .gitignore. 2026-05-20 03:06:58 +08:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml pre-commit: enable codespell checks 2025-05-05 12:34:39 +08:00
.yamllint feat: add a GitHub action to lint the YAML files 2020-12-15 09:52:04 -06:00
AUTHORS AUTHORS: add Eren Terzioglu 2026-05-20 15:17:00 +08:00
CMakeLists.txt cmake: Do not link an executable to detect the compiler. 2026-07-25 22:52:39 +08:00
CONTRIBUTING.md contributing: Add requirement for 'Assisted-by' commit field 2026-07-12 09:42:28 +08:00
INVIOLABLES.md INVIOLABLES.md: Fix a simple alignment and change occurrences of Nuttx 2020-09-03 01:33:05 +08:00
Kconfig sched/misc/assert: Add CONFIG_SCHED_DUMP_TASKS and CONFIG_SCHED_DUMP_STACK 2026-06-09 08:04:54 -04:00
LICENSE libs/libdsp: Add Matrix operations 2026-07-11 14:55:59 -03:00
Makefile !boards: enforce secure ROMFS passwd and TEA key setup 2026-07-09 22:41:11 +08:00
NOTICE Remove the double blank line from source files 2022-02-20 20:10:14 +01:00
README.md ci/testing: Add MemBrowse Integration 2026-06-18 12:07:41 -03:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

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Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).

For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.

Getting Started

First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.

Documentation

You can find the current NuttX documentation on the Documentation Page.

Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.

The old NuttX documentation is still available in the Apache wiki.

Supported Boards

NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.

Contributing

If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.

License

The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.