Javinator9889 opened a new pull request, #15320: URL: https://github.com/apache/nuttx/pull/15320
## Summary The POSIX standard states that the `syslog()` function generates the body from the message and arguments the same way as `printf()`, > except that the additional conversion specification `%m` shall be recognized; *https://pubs.opengroup.org/onlinepubs/009695399/functions/syslog.html* What most of the implementations do is to leverage the processing to `vsprintf` internals, to reduce code duplicity. This means the `%m` modifier is present on almost all `printf` implementations. Take the following code snippet as an example: https://onlinegdb.com/YdR9pU6KS. Therefore, the underlying library must also be updated for `syslog` to support such a specification. ## Impact All the code using `vsprintf` underneath will have the ability to use the `%m` modifier, which is a wrapper for `%s` and `strerror(errno)`. This is not a problem at all as such a modifier was previously ignored, and does not increase the processing significantly because it relies on existing code. Additionally, this change is needed for NuttX to be POSIX-compliant. Otherwise, it is not following the implementation. ## Testing To verify this change, I: 1. Modified the `defconfig` of the `sim:nsh` target, enabling `CONFIG_LIBC_STRERROR` and `CONFIG_LIBC_STRERROR_ERRNUM` - this is only required to have meaningful messages. 2. For the NuttX Apps repo, apply the following patch: [0001-Test-POSIX-syslog-Add-demo-application.patch](https://github.com/user-attachments/files/18230529/0001-Test-POSIX-syslog-Add-demo-application.txt). The patch adds a demo command called `syslog` that generates a random `errno` and outputs it through `syslog` using the `%m` modifier. 3. Build and run the application: * `tools/configure.sh sim:nsh` * `make` * `./nuttx` Running the `syslog` command should output something like:  -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
