include/stdio.h: Hide the kernel file system types from kernel-build programs. by casaroli · Pull Request #20565 · apache/nuttx

casaroli · 2026-10-09T14:22:59Z

Summary

stdio.h includes nuttx/fs/fs.h and nuttx/lib/lib.h. So every program that includes stdio.h also sees the kernel's struct file, struct inode and the other file system types. A program that defines its own struct file does not compile: error: redefinition of 'struct file'.

This PR makes stdio.h stop including nuttx/lib/lib.h in all builds (review), and nuttx/fs/fs.h in the user space of a kernel build (CONFIG_BUILD_KERNEL and not __KERNEL__), where programs cannot use those types. Kernel code, and flat and protected builds, still get fs.h. Removing it for every build breaks many files that rely on the indirect include; that can be a later PR.

stdio.h now defines what it needs itself: the fopencookie() callback types, struct file_struct and its __FS_FLAG_* flags, which were in nuttx/fs/fs.h, and the declaration of lib_get_stream(), which stdin, stdout and stderr expand to. struct streamlist moves from nuttx/fs/fs.h to nuttx/tls.h, where struct task_info_s holds the stream list. nuttx/tls.h includes stdio.h for struct file_struct. No nuttx/fs/cookie.h is needed: stdio.h no longer reaches nuttx/tls.h (the old path was stdio.h -> lib.h -> kmalloc.h -> sched.h -> tls.h).

The files that used lib.h, kmalloc.h, stdlib.h or unistd.h names through stdio.h now include what they use (69 files in drivers, arch, boards, fs, sched and libs).

The old nxstyle errors of the changed files, and the tools/nxstyle.c fix they need, were merged in #20621. This PR is now the stdio.h commit only.

Impact

Code that used names from nuttx/lib/lib.h, nuttx/kmalloc.h, nuttx/sched.h, stdlib.h or unistd.h through stdio.h must include those headers itself. This includes 44 apps files, fixed in apache/nuttx-apps#3839. Its description lists them and how they were found: every apps C file compiled against master and against this PR, for four configurations.

Testing

A program that defines its own struct file and includes <stdio.h>, built outside the tree against the qemu-armv8a:knsh export package and run in QEMU 11:

Before:

ownfile.c:5:8: error: redefinition of 'struct file'

After:

nsh> ownfile
ownfile: struct file value 42

Builds with -Wno-cpp -Werror and apps master. The kernel builds marked (i) also run make export and the apps make import.

Kernel builds: qemu-armv8a:knsh (i), imx93-evk:knsh, qemu-armv7a:knsh (i), sabre-6quad:netknsh (i), rv-virt:knsh, rv-virt:knetnsh64 (i), rv-virt:kfb64, rv-virt:knsh_paging, icicle:knsh, canmv230:knsh, esp32s3-devkit:kernel_n8r2, mps3-an547:knsh.
Flat and protected: lm3s6965-ek:qemu-flat, lm3s6965-ek:qemu-protected, mps2-an500:nsh, qemu-armv8a:nsh, esp32-devkitc:nsh, esp32-devkitc:adc, rv-virt:nsh64, sabre-6quad:nsh, stm32f4discovery:nsh, spresense:wifi_smp, nucleo-f302r8:ihm07m1_b16, esp32c6-devkitc:mpu60x0, ox64:adc, mikroe-stm32f4:fulldemo, tm4c1294-launchpad:nsh, xmc4800-relax:nsh, icicle:rpmsg-ch2, and 19 more configurations of a sweep chosen for many drivers and apps.
Fail only in the apps files above: esp32c6-devkitc:oa_tc6, qemu-armv7a:full (its libcxx and mbedtls errors are on master too), stm32f746g-disco:dropbear, linum-stm32h753bi:zbus.
Fail on master too: sama5d4-ek:knsh, sama5d4-ek:nxwm (sam_mck_frequency), sim:nsh on macOS.

tools/checkpatch.sh -c -u -m -g passes.

depends-on: apache/nuttx-apps/pull/3839

github-actions · 2026-10-09T16:18:57Z

MemBrowse Memory Report

No memory changes detected for:

github-actions · 2026-10-09T21:45:40Z

🔗 Cross-repo PR dependencies

The read-only Build run reported the following dependent PR(s) and fetched head SHA(s):

nshlib, testing/ostest: Include the headers that are used. nuttx-apps#3820 @ 2473ef82a4
netutils/codecs: Include errno.h in md5.c. nuttx-apps#3823 @ 722c63c531

CI run: https://github.com/apache/nuttx/actions/runs/37943764063

casaroli · 2026-10-12T12:39:16Z

@linguini1 I moved the nxstyle commit, and the tools/nxstyle.c fix it needs, to #20621. When it is merged, this PR keeps only the stdio.h commit.

github-actions · 2026-10-12T16:54:51Z

🔗 Cross-repo PR dependencies

The read-only Build run reported the following dependent PR(s) and fetched head SHA(s):

apps: Include the headers that are used. nuttx-apps#3839 @ 5080d13543

CI run: https://github.com/apache/nuttx/actions/runs/38248342757

acassis · 2026-10-12T19:42:01Z

@casaroli please fix:

netpkt_ethercat.c: In function 'netpkt_ethercat_main':
Error: netpkt_ethercat.c:89:16: error: implicit declaration of function 'atoi' [-Werror=implicit-function-declaration]
   89 |       repeat = atoi(argv[2]);
      |                ^~~~
Error: netpkt_ethercat.c:95:7: error: implicit declaration of function 'close'; did you mean 'pclose'? [-Werror=implicit-function-declaration]
   95 |       close(sockfd);
      |       ^~~~~
      |       pclose
Error: netpkt_ethercat.c:125:7: error: implicit declaration of function 'usleep' [-Werror=implicit-function-declaration]
  125 |       usleep(1000);
      |       ^~~~~~

#20565 adds include directives to these files, and the check job runs nxstyle on the whole of every changed file. Their nxstyle errors are older than the change: braces, case labels and comments in the wrong column, missing blank lines after declarations, and long lines. Only the layout changes. With all white space and comment margins removed, every file is identical to the old one, except two: iconv() and stm32_touchscreen.c get braces around one-line statements, and getpass() gets a break aligned. The object code of the three libc files is identical before and after on qemu-armv8a:nsh with LIBC_LOCALE. Assisted-by: Claude Code:claude-opus-5-5 Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>

github-actions · 2026-10-13T05:13:31Z

🔗 Cross-repo PR dependencies

The read-only Build run reported the following dependent PR(s) and fetched head SHA(s):

apps: Include the headers that are used. nuttx-apps#3839 @ c6ea72bd4e

CI run: https://github.com/apache/nuttx/actions/runs/38346358795

…programs. stdio.h included nuttx/fs/fs.h and nuttx/lib/lib.h, so every program that includes stdio.h saw the kernel's struct file, struct inode and the other file system types. A program that defines its own struct file does not compile. stdio.h no longer includes nuttx/lib/lib.h in any build, and includes nuttx/fs/fs.h only for kernel code and for flat and protected builds. In the user space of a kernel build (CONFIG_BUILD_KERNEL and not __KERNEL__) programs cannot use the file system types anyway, so they do not see them. Doing the same for flat and protected builds breaks many files that rely on the indirect include. stdio.h now defines what it needs itself: the fopencookie() callback types, struct file_struct and its __FS_FLAG_* flags, which were in nuttx/fs/fs.h, and the declaration of lib_get_stream(), which stdin, stdout and stderr expand to. struct streamlist moves from nuttx/fs/fs.h to nuttx/tls.h, where struct task_info_s holds the stream list. nuttx/tls.h includes stdio.h for struct file_struct. The files that used kernel types or other headers through stdio.h now include what they use. Assisted-by: Claude Code:claude-opus-5-5 Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com>

github-actions · 2026-10-13T20:15:58Z

🔗 Cross-repo PR dependencies

The read-only Build run reported the following dependent PR(s) and fetched head SHA(s):

apps: Include the headers that are used. nuttx-apps#3839 @ 20fb2df237

CI run: https://github.com/apache/nuttx/actions/runs/38364521591

casaroli requested review from Donny9, GUIDINGLI, btashton, jerpelea, pkarashchenko, pussuw, xiaoxiang781216 and yamt as code owners October 9, 2026 14:23

xiaoxiang781216 reviewed Oct 9, 2026

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Comment thread include/stdio.h

github-actions Bot added Area: File System File System issues Area: OS Components OS Components issues Size: M The size of the change in this PR is medium labels Oct 9, 2026

casaroli mentioned this pull request Oct 11, 2026

netutils/netcat, system/nxinit: Include the headers that are used. apache/nuttx-apps#3831

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casaroli force-pushed the libc-stdio-kernel-types branch from 896862b to c383513 Compare October 11, 2026 05:56

xiaoxiang781216 reviewed Oct 11, 2026

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Comment thread include/nuttx/fs/cookie.h Outdated

Comment thread include/stdio.h

casaroli requested review from davids5, johannes-nivus, michallenc and tmedicci as code owners October 11, 2026 16:24

xiaoxiang781216 reviewed Oct 12, 2026

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Comment thread include/nuttx/fs/cookie.h Outdated

Comment thread include/stdio.h Outdated

casaroli force-pushed the libc-stdio-kernel-types branch from 6b508c0 to 3db73ba Compare October 12, 2026 05:49

casaroli requested review from Ouss4, anchao, eren-terzioglu, fdcavalcanti, linguini1, lupyuen and masayuki2009 as code owners October 12, 2026 05:49

xiaoxiang781216 approved these changes Oct 12, 2026

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acassis previously approved these changes Oct 12, 2026

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casaroli force-pushed the libc-stdio-kernel-types branch from 77d0912 to 516eb56 Compare October 13, 2026 04:25

xiaoxiang781216 previously approved these changes Oct 13, 2026

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github-actions Bot added Size: M The size of the change in this PR is medium and removed Size: XL The size of the change in this PR is very large. Consider breaking down the PR into smaller pieces. labels Oct 13, 2026

casaroli dismissed stale reviews from xiaoxiang781216 and acassis via c393b35 October 13, 2026 05:25

casaroli force-pushed the libc-stdio-kernel-types branch 2 times, most recently from c393b35 to 9a38e62 Compare October 13, 2026 06:34

casaroli force-pushed the libc-stdio-kernel-types branch from 9a38e62 to 0c8dcf1 Compare October 13, 2026 07:43

jerpelea approved these changes Oct 13, 2026

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casaroli requested review from acassis and xiaoxiang781216 October 13, 2026 12:21

xiaoxiang781216 approved these changes Oct 13, 2026

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acassis approved these changes Oct 13, 2026

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acassis merged commit f6e5be7 into apache:master Oct 13, 2026
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xiaoxiang781216 mentioned this pull request Oct 14, 2026

[BUG] stdio.h include nuttx/fs/fs.h nuttx/lib/lib.h Leading to duplicate definitions with third-party libraries #14260

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include/stdio.h: Hide the kernel file system types from kernel-build programs. - #20565

include/stdio.h: Hide the kernel file system types from kernel-build programs.#20565
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