Flag to compile oneTBB without threads

CMakeLists.txt

@@ -1,4 +1,4 @@
-# Copyright (c) 2020-2023 Intel Corporation
+# Copyright (c) 2020-2024 Intel Corporation
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -194,7 +194,7 @@ endif()
 # -------------------------------------------------------------------
 # Common dependencies
 #force -pthread during compilation for Emscripten
-if (EMSCRIPTEN)
+if (EMSCRIPTEN AND NOT EMSCRIPTEN_WITHOUT_PTHREAD)
    set(THREADS_HAVE_PTHREAD_ARG TRUE)
 endif()
 

WASM_Support.md

@@ -34,10 +34,12 @@ To build the system, run:
 ```
 mkdir build && cd build
 emcmake cmake .. -DCMAKE_CXX_COMPILER=em++ -DCMAKE_C_COMPILER=emcc -DTBB_STRICT=OFF -DCMAKE_CXX_FLAGS=-Wno-unused-command-line-argument -DTBB_DISABLE_HWLOC_AUTOMATIC_SEARCH=ON -DBUILD_SHARED_LIBS=ON -DTBB_EXAMPLES=ON -DTBB_TEST=ON
+```
+To compile oneTBB without ``pthreads``, set the flag ``-DEMSCRIPTEN_WITHOUT_PTHREAD=true`` in the command above. By default, oneTBB uses the ``pthreads``.
+```
 cmake --build . <options>
 cmake --install . <options>
 ```
-
 Where:
 
 * ``emcmake`` - a tool that sets up the environment for Emscripten*. 

cmake/compilers/Clang.cmake

@@ -1,4 +1,4 @@
-# Copyright (c) 2020-2023 Intel Corporation
+# Copyright (c) 2020-2024 Intel Corporation
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -16,7 +16,9 @@ if (EMSCRIPTEN)
   set(TBB_EMSCRIPTEN 1)
   set(TBB_COMMON_COMPILE_FLAGS ${TBB_COMMON_COMPILE_FLAGS} -fexceptions)
   set(TBB_TEST_LINK_FLAGS  ${TBB_COMMON_LINK_FLAGS} -fexceptions -sINITIAL_MEMORY=65536000 -sALLOW_MEMORY_GROWTH=1 -sEXIT_RUNTIME=1)
-  set_property(TARGET Threads::Threads PROPERTY INTERFACE_LINK_LIBRARIES "-pthread")
+  if (NOT EMSCRIPTEN_WITHOUT_PTHREAD)
+      set_property(TARGET Threads::Threads PROPERTY INTERFACE_LINK_LIBRARIES "-pthread")
+  endif()
 endif()
 
 if (MINGW)