# configUSE\_NEWLIB\_REENTRANT with IAR **URL:** \ **Category:** Kernel\ **Created:** [May 10, 2022, 9:06am UTC](https://forums.freertos.org/t/configuse-newlib-reentrant-with-iar/15034 "2022-05-10T09:06:44Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![snahmad](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/snahmad/32/2491_2.png) [@snahmad](https://forums.freertos.org/u/snahmad)\ **Post date:** [May 10, 2022, 9:06am UTC](https://forums.freertos.org/t/configuse-newlib-reentrant-with-iar/15034/1 "2022-05-10T09:06:44Z")
hi, I need to enable configUSE\_NEWLIB\_REENTRANT 1 with IAR. IAR compiler donot provide reent.h. Any example freeRTOS for IAR with configUSE\_NEWLIB\_REENTRANT 1 I am using memory 4 of freertos. do I need to enable configUSE\_NEWLIB\_REENTRANT Thanks, Syed ---
**Author:** ![richard-damon](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/richard-damon/32/38_2.png) [@richard-damon](https://forums.freertos.org/u/richard-damon)\ **Post date:** [May 10, 2022, 11:34am UTC](https://forums.freertos.org/t/configuse-newlib-reentrant-with-iar/15034/2 "2022-05-10T11:34:24Z")
If they don’t provide reent.h, then either they aren’t using newlib, or they have configured it for only the simpler cases that don’t use that option. Note, that configUSE\_NEWLIB\_REENTRANT is only needed if you are using library functions out of newlib that need to keep “local” information between calls. This would be things like strtok, or the io library. I find I rarely need to use that option. ---
**Author:** ![rtel](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/rtel/32/31_2.png) [@rtel](https://forums.freertos.org/u/rtel)\ **Post date:** [May 10, 2022, 2:12pm UTC](https://forums.freertos.org/t/configuse-newlib-reentrant-with-iar/15034/3 "2022-05-10T14:12:13Z")
If you are using the IAR tools I would recommend using their libraries too. They are tailored for embedded systems and part of the value of their tools.