with wasi-sdk-p2.cmake, the pthread can't be detected when build with CMake project

[zhuyipeng]

hi, all,

I am trying to compile mqtt into webassembly, cmake come out pthread detect error as followed showing. I went with wasi-sdk-pthread.cmake, pthread check passed.

does anyone encounter this issue? how should I fix it?

`cmake -DCMAKE_TOOLCHAIN_FILE=/mnt/d/UserData/z003n71c/workspace/wasi-sdk/build/install/share/cmake/wasi-sdk-p2.cmake -DWITH_TLS=OFF -DWITH_UNIX_SOCKETS=OFF ..
-- The C compiler identification is Clang 19.1.5
-- The CXX compiler identification is Clang 19.1.5
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /mnt/d/UserData/z003n71c/workspace/wasi-sdk/build/install/bin/clang - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /mnt/d/UserData/z003n71c/workspace/wasi-sdk/build/install/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- WITH_DLT = OFF
-- Could NOT find cJSON (missing: CJSON_INCLUDE_DIR CJSON_LIBRARY)
-- Optional dependency cJSON not found. Some features will be disabled.
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Failed
-- Check if compiler accepts -pthread
-- Check if compiler accepts -pthread - no
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - not found
CMake Error at /usr/local/cmake-4.0.0-rc3-linux-x86_64/share/cmake-4.0/Modules/FindPackageHandleStandardArgs.cmake:227 (message):
Could NOT find Threads (missing: Threads_FOUND)
Call Stack (most recent call first):
/usr/local/cmake-4.0.0-rc3-linux-x86_64/share/cmake-4.0/Modules/FindPackageHandleStandardArgs.cmake:591 (_FPHSA_FAILURE_MESSAGE)
/usr/local/cmake-4.0.0-rc3-linux-x86_64/share/cmake-4.0/Modules/FindThreads.cmake:226 (find_package_handle_standard_args)
lib/CMakeLists.txt:97 (find_package)

-- Configuring incomplete, errors occurred!`

[alexcrichton]

This is currently expected, wasm32-wasip2 doesn't support pthreads. That's different from wasm32-wasip1-threads, which wasi-sdk-pthread.cmake uses, which does support pthreads.

[zhuyipeng]

@alexcrichton thanks for your quickly feedback, however if I use wasm32-wasip1-threads, the sockets will not be supported. :( any suggestion here? by the way, if the module need interface of 'getaddrinfo' and I see wasi-sdk will not support it, any replace interface I could use? thank you.

[alexcrichton]

If you want multithreaded sockets, you'll need to wait for https://github.com/WebAssembly/shared-everything-threads, a wasm proposal which will help enable multithreading in the component model. The time-scale of that is likely on the scale of years though.