GNU Arm Embedded Toolchain

headers and/or preprocessor defines for newlib nano

Asked by Sergei Sharonov

Hello,
Is there a guide/howto on how to configure toolchain to use newlib nano? Let's say we pass "-specs=nano.spec" to linker. Now we need to make sure our headers match precompiled newlib nano binaries. I figure one way of doing it is do pass some defines to preprocessor. e.g.:
-D_REENT_SMALL and -D_REENT_GLOBAL_ATEXIT
Otherwise library and application will have different notion of struct _reent guts and cause a lots of weird problems.
I am not sure if any others defines are needed. What is the "officially approved" way of configuring this?
Thank you,
Sergei

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Andre Vieira (andre-simoesdiasvieira) said : 		#1

Hi Sergei,

This is a known issue and it should be fixed in the 4.9 Q3 release.

Best Regards,

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Ahmed Ammar (ahmed-a-ammar) said : 		#2

It seems that this is fixed with the Q3 release for me, -D_REENT_SMALL -D_REENT_GLOBAL_ATEXIT, now work, it was causing segfaults on clean boots with Q2.

I don't see any mention of this in the release notes, is it related to 'macro mismatch fix'?

Thanks.

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Sergei Sharonov (sergei-7) said : 		#3

Well, -D_REENT_SMALL and -D_REENT_GLOBAL_ATEXIT are working in 2015q1 release for me. The question was if there are any other defines necessary for newlib nano. I found the need for the above defines through debugging several random crashes and it was quite painful. I hate to think there may be some other defines needed that I do not know about.
Regards,
Sergei

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Andre Vieira (andre-simoesdiasvieira) said : 		#4

Hi Sergei,

You shouldn't need to manually pass the macro definitions with the q3 release, if you use -specs=nano.specs it will include 'arm-none-eabi/include/newlib-nano/newlib.h' which is the header file that was used to build the nano version of newlib. So with this you need not think about all the other defines .

Hope this eases your mind.

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