No libc++ Support On Windows 11

[SmushyTaco]

This code:

#include <print>
#include <scn/scan.h>
using namespace std;
using namespace scn;
int main() {
    if (auto result {prompt<int>("Enter your favorite number: ", "{}")}) {
        println("Your favorite number is \"{}\"!", result->value());
    } else {
        println(stderr, "Error: {}", result.error().msg());
    }
}

With this CMake file:

cmake_minimum_required(VERSION 3.29)
include(FetchContent)
project(untitled1)
set(CMAKE_CXX_STANDARD 23)
set(CMAKE_CXX_EXTENSIONS OFF)
if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_FRONTEND_VARIANT MATCHES "GNU")
    add_link_options(-fuse-ld=lld)
    add_compile_options(-stdlib=libc++)
endif()
if(MSVC)
    add_compile_options(/Wall)
else()
    add_compile_options(-Wall -Wextra -Wpedantic)
endif()
FetchContent_Declare(
        scn
        GIT_REPOSITORY  https://github.com/eliaskosunen/scnlib
        GIT_TAG         v2.0.2
        GIT_SHALLOW     TRUE
)
FetchContent_MakeAvailable(scn)
add_executable(untitled1 main.cpp)
target_link_libraries(untitled1 PRIVATE scn::scn)
if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_COMPILER_FRONTEND_VARIANT MATCHES "GNU")
    target_link_libraries(untitled1 PRIVATE c++)
endif()

Using Clang 18 and libc++ from MSYS2 as my default toolchain as seen here:

Fails to build with this as the console output:

====================[ Build | untitled1 | Debug ]===============================
C:\msys64\ucrt64\bin\cmake.exe --build C:\Users\organ\CLionProjects\untitled1\cmake-build-debug --target untitled1 -j 30
[1/16] Scanning C:/Users/organ/CLionProjects/untitled1/main.cpp for CXX dependencies
FAILED: CMakeFiles/untitled1.dir/main.cpp.obj.ddi 
C:\Windows\system32\cmd.exe /C ""C:/msys64/ucrt64/bin/clang-scan-deps.exe" -format=p1689 -- C:\msys64\ucrt64\bin\clang++.exe  -IC:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include -g -std=c++23 -fansi-escape-codes -fcolor-diagnostics -stdlib=libc++ -Wall -Wextra -Wpedantic -DSCN_REGEX_BACKEND=0 -x c++ C:/Users/organ/CLionProjects/untitled1/main.cpp -c -o CMakeFiles\untitled1.dir\main.cpp.obj -resource-dir "C:/msys64/ucrt64/lib/clang/18" -MT CMakeFiles\untitled1.dir\main.cpp.obj.ddi -MD -MF CMakeFiles\untitled1.dir\main.cpp.obj.ddi.d > CMakeFiles\untitled1.dir\main.cpp.obj.ddi.tmp && "C:/msys64/ucrt64/bin/cmake.exe" -E rename CMakeFiles\untitled1.dir\main.cpp.obj.ddi.tmp CMakeFiles\untitled1.dir\main.cpp.obj.ddi"
Error while scanning dependencies for C:/Users/organ/CLionProjects/untitled1/main.cpp:
In file included from C:/Users/organ/CLionProjects/untitled1/main.cpp:2:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/args.h:26:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/error.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/fwd.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/config.h:20:
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:97:5: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:65:5: note: expanded from macro 'SCN_CLANG'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:252:16: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:254:7: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:65:5: note: expanded from macro 'SCN_CLANG'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:256:19: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:258:20: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:283:17: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:310:16: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:374:19: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:640:22: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:119:5: note: expanded from macro 'SCN_GCC_COMPAT'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
In file included from C:/Users/organ/CLionProjects/untitled1/main.cpp:2:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/args.h:26:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/error.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/fwd.h:20:
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp.h:41:5: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:65:5: note: expanded from macro 'SCN_CLANG'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
In file included from C:/Users/organ/CLionProjects/untitled1/main.cpp:2:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/args.h:26:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/error.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/fwd.h:20:
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp.h:77:5: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:119:5: note: expanded from macro 'SCN_GCC_COMPAT'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
In file included from C:/Users/organ/CLionProjects/untitled1/main.cpp:2:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/args.h:26:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/error.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/fwd.h:20:
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp.h:214:5: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:65:5: note: expanded from macro 'SCN_CLANG'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
In file included from C:/Users/organ/CLionProjects/untitled1/main.cpp:2:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/scan.h:20:
In file included from C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/scan.h:21:
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/format_string.h:636:5: error: token is not a valid binary operator in a preprocessor subexpression
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:65:5: note: expanded from macro 'SCN_CLANG'
C:/Users/organ/CLionProjects/untitled1/cmake-build-debug/_deps/scn-src/include/scn/detail/pp_detect.h:54:16: note: expanded from macro 'SCN_COMPILER'
...

If I switch over to GCC (and switch the println statements to cout since GCC doesn't have println support yet), everything works properly because it'll default over to libstdc++, so the issue at hand is using libc++ on Windows 11 with this project.

[eliaskosunen]

Couldn't repro this on latest master. The error looks similar to #110, which has been fixed in master since 7da4041.