Question about the definition of _XOPEN_SOURCE

Sebastian Huber sebastian.huber at
Sun Jan 3 10:04:59 UTC 2021

Hello Heinz,

On 01/01/2021 18:46, Heinz Junkes wrote:
> Please excuse me if this question has already been answered. But unfortunately I have not been able to find a clear statement.
> Why is RTEMS _XOPEN_SOURCE not set with a value when building a BSP with --enable-posix?
> in the rtems-libbsd you can find a definition in some places.
> z.B. in dhcpd/configure -D_XOPEN_SOURCE=700 and
> in glibc-bugs.h #define _XOPEN_SOURCE 500
> That seems a little unstructured to me. I'm sure there's an explanation why this is so complicated. But which value is the correct one e.g. for PowerPC and RTEMS 5.1?

the so called feature test macros should be defined by the application:

Which function is not defined in your setup?

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