[Bug] Failed to build with OpenSSL 4.0.0

[hdu-sdlzx]

Search before asking

• I searched in the issues and found nothing similar.

Version

pulsar v4.1.0
openssl 4.0.0

Minimal reproduce step

build pulsar-client-cpp

What did you expect to see?

build completed successfully

What did you see instead?

In file included from /home/sdlzx/code/pulsar-client-cpp/lib/BatchMessageContainerBase.cc:22:
/home/sdlzx/code/pulsar-client-cpp/lib/MessageCrypto.h:23:10: fatal error: openssl/engine.h: No such file or directory
23 | #include <openssl/engine.h>
| ^~~~~~~~~~~~~~~~~~
compilation terminated.

Anything else?

OpenSSL 4.0.0 has removed engine support.
reference: https://openssl-library.org/post/2026-04-14-openssl-40-final-release/

And I don't think pulsar requires this, in fact, pulsar can be built without this line.

Are you willing to submit a PR?

• I'm willing to submit a PR!