build(cmake): detect compiler version for co_context::generator

Author: Codesire-Deng

cmake/CompileOption.cmake

@@ -51,3 +51,7 @@ target_link_libraries(co_context PUBLIC Threads::Threads)
 if (USE_MIMALLOC)
     target_link_libraries(co_context PUBLIC mimalloc)
 endif()
+
+if (co_context_no_generator) # set by check/check_compile.cmake
+    target_compile_definitions(co_context PRIVATE CO_CONTEXT_NO_GENERATOR)
+endif()

cmake/check/check_compile.cmake

@@ -2,10 +2,22 @@ if(NOT CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
     message(FATAL_ERROR "[g++/clang] is required, but the compiler id is ${CMAKE_CXX_COMPILER_ID}.${CMAKE_CXX_COMPILER_ID} is not supported now")
 endif()
 
-if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "11.3.0")
-    message(FATAL_ERROR "Insufficient gcc version, requires gcc 11.3 or above")
+if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "11.2.0")
+        message(FATAL_ERROR "Insufficient gcc version, requires gcc 11.2 or above")
+    endif()
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "11.3.0")
+        message(NOTICE "co_context::generator will be disabled for insufficient gcc version (requires gcc 11.3 or above).")
+        set(co_context_no_generator ON)
+    endif()
 endif()
 
-if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "14.0.0")
-    message(FATAL_ERROR "Insufficient clang version, requires clang 14.0 or above")
+if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "14.0.0")
+        message(FATAL_ERROR "Insufficient clang version, requires clang 14.0 or above")
+    endif()
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "17.0.0")
+        message(NOTICE "co_context::generator will be disabled for insufficient clang version (requires clang 17 or above).")
+        set(co_context_no_generator ON)
+    endif()
 endif()

example/iota.cpp

@@ -1,4 +1,4 @@
-#if defined(__GNUG__) && !defined(__clang__)
+#ifndef CO_CONTEXT_NO_GENERATOR
 
 #include <co_context/generator.hpp>
 
@@ -22,13 +22,14 @@ int main() {
     return 0;
 }
 
-#else
+#else // ifndef CO_CONTEXT_NO_GENERATOR
 
 #include <iostream>
 
 int main() {
-    std::cout << "This program requires g++ as the compiler. exit..."
-              << std::endl;
+    std::cout
+        << "This program requires g++ 11.3 or clang 17 as the compiler. exit..."
+        << std::endl;
     return 0;
 }
 

include/co_context/all.hpp

@@ -14,6 +14,6 @@
 #include <co_context/utility/defer.hpp>
 #include <co_context/utility/polymorphism.hpp>
 
-#if defined(__GNUG__) && !defined(__clang__)
+#ifndef CO_CONTEXT_NO_GENERATOR
 #include <co_context/generator.hpp>
 #endif

include/co_context/generator.hpp

@@ -3,12 +3,14 @@
 // Authors: Casey Carter, Lewis Baker, Corentin Jabot.
 // https://godbolt.org/z/5hcaPcfvP
 //
-// NOLINTBEGIN
 #pragma once
-#if !defined(__GNUG__) || defined(__clang__)
-#error Up to now this header can only be compiled by g++.
-#error PS: Clang 14/16 is known to be not happy with this header.
-#endif
+#ifdef CO_CONTEXT_STD_GENERATOR
+#include <generator>
+
+namespace co_context {
+using std::generator;
+}
+#elif !defined(CO_CONTEXT_NO_GENERATOR)
 #pragma GCC system_header
 #include <algorithm>
 #include <cassert>
@@ -34,7 +36,7 @@
 #define NO_UNIQUE_ADDRESS [[no_unique_address]]
 #endif
 
-// namespace std {
+// NOLINTBEGIN
 namespace co_context {
 
 struct alignas(__STDCPP_DEFAULT_NEW_ALIGNMENT__) _Aligned_block {
@@ -622,3 +624,4 @@ class generator
 } // namespace co_context
 
 // NOLINTEND
+#endif

test/CMakeLists.txt

@@ -11,6 +11,7 @@ set(co_context_tests
         liburingcxx_netcat
         move_shared_task
         mpl_type_list
+        generator_test
 )
 
 foreach(test_target ${co_context_tests})

test/generator_test.cppx renamed to test/generator_test.cpp

@@ -1,3 +1,4 @@
+#ifndef CO_CONTEXT_NO_GENERATOR
 #include <co_context/generator.hpp>
 
 /////////////////////////////////////////////////////////////////////////////
@@ -49,7 +50,8 @@ co_context::generator<uint64_t, uint64_t> nested_sequences_example() {
     );
 #else
     co_yield co_context::ranges::elements_of{
-        std::array<const uint64_t, 5>{2, 4, 6, 8, 10}};
+        std::array<const uint64_t, 5>{2, 4, 6, 8, 10}
+    };
 #endif
     std::printf("yielding elements_of nested co_context::generator\n");
     co_yield co_context::ranges::elements_of{fib(10)};
@@ -316,6 +318,20 @@ int main() {
 
     stateful_alloc_example(std::allocator_arg, stateful_allocator<double>{42});
 
-    [[maybe_unused]] member_coro m;
+    [[maybe_unused]]
+    member_coro m;
     assert(*m.f().begin() == 42);
 }
+
+#else // ifndef CO_CONTEXT_NO_GENERATOR
+
+#include <iostream>
+
+int main() {
+    std::cout
+        << "This program requires g++ 11.3 or clang 17 as the compiler. exit..."
+        << std::endl;
+    return 0;
+}
+
+#endif