FW: Strange warnings while linking to openssl version 1.1.1k

[Michael Wojcik]

> From: openssl-users <openssl-users-bounces at openssl.org> On Behalf Of Robert Smith via openssl-users
> Sent: Monday, 12 April, 2021 14:52

Your message has a Reply-to header set, directing replies to you rather than to the list. Don't do that; it's rude. Ask a question here, read the reply here. Other people may be interested in the responses.

> I am getting the following warning while linking my app to openssl version 1.1.1k.
> Could you advise what can cause these warnings and how to resolve them?
> ../../../artifacts/openssl/arm3531/lib/libcrypto.a(async_posix.o): In function `ASYNC_is_capable':
> async_posix.c:(.text+0x48): warning: warning: getcontext is not implemented and will always fail

DuckDuckGo is your friend. The first hit for "getcontext is not implemented and will always fail" explains that this is an ARM issue, not an OpenSSL one. Another hit a little further down provides more details. See:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=369453

No one has implemented getcontext, etc, for ARM yet. Consequently they don't work. The warning messages are emitted by the GNU toolchain, which knows the context functions are not available on this platform.

OpenSSL can detect this at runtime - see ASYNC_is_capable() in async_posix.c, and its use in e.g. speed.c. Since there is no viable async implementation on Linux-ARM, you won't be able to use the OpenSSL async-job APIs, as described in the OpenSSL docs. If you don't need those APIs, these warnings are irrelevant.

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Michael Wojcik