On Mar 11, 2021, at 11:51 AM, Rob Meades via lists.zephyrproject.org <Rob.Meades=u-blox.com@lists.zephyrproject.org> wrote:

Should I expect C library functions (e.g. strtok()) under Zephyr to be re-entrant or must I call the re-entrant versions (i.e. in this case strtok_r())?

I ask because I am building/running nRF52840 (cortex-m4) and strok() _appears_ to NOT be re-entrant: I'd like to understand if this is expected or if I've messed up a configuration somewhere. My prj.conf file is attached in case it is helpful in answering the question.

Rob





<prj.conf>

On Mar 11, 2021, at 11:51 AM, Rob Meades via lists.zephyrproject.org <Rob.Meades=u-blox.com@lists.zephyrproject.org> wrote:

Should I expect C library functions (e.g. strtok()) under Zephyr to be re-entrant or must I call the re-entrant versions (i.e. in this case strtok_r())?

I ask because I am building/running nRF52840 (cortex-m4) and strok() _appears_ to NOT be re-entrant: I'd like to understand if this is expected or if I've messed up a configuration somewhere. My prj.conf file is attached in case it is helpful in answering the question.

Rob





<prj.conf>

On Mar 11, 2021, at 12:04 PM, Rob Meades <Rob.Meades@u-blox.com> wrote:

Thanks for the swift response. That's a shame. I will go look at the PR at your link as shifting to the re-entrant versions just for Zephyr is going to be painful.

Rob
-----Original Message-----
From: users@lists.zephyrproject.org <users@lists.zephyrproject.org> On Behalf Of Kumar Gala
Sent: 11 March 2021 17:54
To: Rob Meades <Rob.Meades@u-blox.com>
Cc: users@lists.zephyrproject.org
Subject: Re: [Zephyr-users] C library re-entrancy under Zephyr

*** This is an EXTERNAL email. It was sent from outside of u-blox. ***

Re-entrant support between newlib and zephyr is not currently supported.

There’s an old PR on the subject

https://github.com/zephyrproject-rtos/zephyr/pull/21518

- k

On Mar 11, 2021, at 11:51 AM, Rob Meades via lists.zephyrproject.org <Rob.Meades=u-blox.com@lists.zephyrproject.org> wrote:

Should I expect C library functions (e.g. strtok()) under Zephyr to be re-entrant or must I call the re-entrant versions (i.e. in this case strtok_r())?

I ask because I am building/running nRF52840 (cortex-m4) and strok() _appears_ to NOT be re-entrant: I'd like to understand if this is expected or if I've messed up a configuration somewhere. My prj.conf file is attached in case it is helpful in answering the question.

Rob





<prj.conf>

Just to be clear on this, is it true that re-entrancy is not supported by Zephyr for any of the newlib stdio.h or stdlib.h functions, so not just the likes of strok() but also snprintf() and, more fundamentally, malloc()/free()?

If this is the case, are there any other C libraries (so not newlib) for which Zephyr does support re-entrancy and which fulfil the same functions?

Rob

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