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Because Z_CBPRINTF_STATIC_PACKAGE_GENERIC()'s first argument can be a static memory location and we have `-Wall`, which implicitly enables `-Waddress`, we get the following warnings when you enable `EXTRA_CFLAGS=-save-temps=obj`. $ west build -b qemu_cortex_m3 samples/hello_world -- \ -DEXTRA_CFLAGS=-save-temps=obj : : zephyr/kernel/fatal.c: In function 'k_sys_fatal_error_handler': zephyr/kernel/fatal.c:45:1125: warning: the comparison will always evaluate as 'true' for the address of 'data' will never be NULL [-Waddress] 45 | LOG_ERR("Halting system"); | In file included from zephyr/include/zephyr/logging/log_backend.h:9, from zephyr/include/zephyr/logging/log_ctrl.h:10, from zephyr/kernel/fatal.c:13: .../include/zephyr/logging/log_msg.h:94:17: note: 'data' declared here 94 | uint8_t data[]; | ^~~~ The reason why you don't see this warning without the flag is that GCC tracks tokens and suppress the warning if it's from a macro expansion. You can disable this feature by adding `-ftrack-macro-expansion=0`: west build -b qemu_cortex_m3 samples/hello_world -- \ -DEXTRA_CFLAGS=-ftrack-macro-expansion=0 Because `-save-temps` generates .i files, all macros have been expanded and the information has already been lost. All GCC sees at the compilation stage are the comparisons of static memory locations. This commit replaces `buf != NULL` with a static inline function `___is_null()` to silence the compiler. By passing a static memory location to a function, the compiler doesn't see the comparisons of a static memory locations against literal values. But it's still able to optimize out in the later stage. There is another way to silence it; By ignoring `-Waddress` with a pragma. But its effect is the macro wide and it's too wide IMHO. Thus, I've decided to go with the inline function. To add one more note: The name `___is_null()` is obviously too generic. But let's have it here until someone finds it problematic. This closes #51528. Signed-off-by: Yasushi SHOJI <yashi@spacecubics.com> |
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boards | ||
cmake | ||
doc | ||
drivers | ||
dts | ||
include/zephyr | ||
kernel | ||
lib | ||
misc | ||
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samples | ||
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share | ||
soc | ||
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CMakeLists.txt | ||
CODE_OF_CONDUCT.md | ||
CODEOWNERS | ||
CONTRIBUTING.rst | ||
Kconfig | ||
Kconfig.zephyr | ||
LICENSE | ||
MAINTAINERS.yml | ||
README.rst | ||
VERSION | ||
version.h.in | ||
west.yml | ||
zephyr-env.cmd | ||
zephyr-env.sh |
.. raw:: html <a href="https://www.zephyrproject.org"> <p align="center"> <picture> <source media="(prefers-color-scheme: dark)" srcset="doc/_static/images/logo-readme-dark.svg"> <source media="(prefers-color-scheme: light)" srcset="doc/_static/images/logo-readme-light.svg"> <img src="doc/_static/images/logo-readme-light.svg"> </picture> </p> </a> <a href="https://bestpractices.coreinfrastructure.org/projects/74"><img src="https://bestpractices.coreinfrastructure.org/projects/74/badge"></a> <a href="https://github.com/zephyrproject-rtos/zephyr/actions/workflows/twister.yaml?query=branch%3Amain"> <img src="https://github.com/zephyrproject-rtos/zephyr/actions/workflows/twister.yaml/badge.svg?event=push"></a> The Zephyr Project is a scalable real-time operating system (RTOS) supporting multiple hardware architectures, optimized for resource constrained devices, and built with security in mind. The Zephyr OS is based on a small-footprint kernel designed for use on resource-constrained systems: from simple embedded environmental sensors and LED wearables to sophisticated smart watches and IoT wireless gateways. The Zephyr kernel supports multiple architectures, including ARM (Cortex-A, Cortex-R, Cortex-M), Intel x86, ARC, Nios II, Tensilica Xtensa, and RISC-V, SPARC, MIPS, and a large number of `supported boards`_. .. below included in doc/introduction/introduction.rst Getting Started *************** Welcome to Zephyr! See the `Introduction to Zephyr`_ for a high-level overview, and the documentation's `Getting Started Guide`_ to start developing. .. start_include_here Community Support ***************** Community support is provided via mailing lists and Discord; see the Resources below for details. .. _project-resources: Resources ********* Here's a quick summary of resources to help you find your way around: * **Help**: `Asking for Help Tips`_ * **Documentation**: http://docs.zephyrproject.org (`Getting Started Guide`_) * **Source Code**: https://github.com/zephyrproject-rtos/zephyr is the main repository; https://elixir.bootlin.com/zephyr/latest/source contains a searchable index * **Releases**: https://github.com/zephyrproject-rtos/zephyr/releases * **Samples and example code**: see `Sample and Demo Code Examples`_ * **Mailing Lists**: users@lists.zephyrproject.org and devel@lists.zephyrproject.org are the main user and developer mailing lists, respectively. You can join the developer's list and search its archives at `Zephyr Development mailing list`_. The other `Zephyr mailing list subgroups`_ have their own archives and sign-up pages. * **Nightly CI Build Status**: https://lists.zephyrproject.org/g/builds The builds@lists.zephyrproject.org mailing list archives the CI nightly build results. * **Chat**: Real-time chat happens in Zephyr's Discord Server. Use this `Discord Invite`_ to register. * **Contributing**: see the `Contribution Guide`_ * **Wiki**: `Zephyr GitHub wiki`_ * **Issues**: https://github.com/zephyrproject-rtos/zephyr/issues * **Security Issues**: Email vulnerabilities@zephyrproject.org to report security issues; also see our `Security`_ documentation. Security issues are tracked separately at https://zephyrprojectsec.atlassian.net. * **Zephyr Project Website**: https://zephyrproject.org .. _Discord Invite: https://chat.zephyrproject.org .. _supported boards: http://docs.zephyrproject.org/latest/boards/index.html .. _Zephyr Documentation: http://docs.zephyrproject.org .. _Introduction to Zephyr: http://docs.zephyrproject.org/latest/introduction/index.html .. _Getting Started Guide: http://docs.zephyrproject.org/latest/develop/getting_started/index.html .. _Contribution Guide: http://docs.zephyrproject.org/latest/contribute/index.html .. _Zephyr GitHub wiki: https://github.com/zephyrproject-rtos/zephyr/wiki .. _Zephyr Development mailing list: https://lists.zephyrproject.org/g/devel .. _Zephyr mailing list subgroups: https://lists.zephyrproject.org/g/main/subgroups .. _Sample and Demo Code Examples: http://docs.zephyrproject.org/latest/samples/index.html .. _Security: http://docs.zephyrproject.org/latest/security/index.html .. _Asking for Help Tips: https://docs.zephyrproject.org/latest/develop/getting_started/index.html#asking-for-help