[fix] error: module file CMakeFiles/__cmake_cxx23.dir/std.pcm cannot be loaded due to a configuration mismatch with the current compilation #4279 #4582
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…n warnings are generated
…n warnings are generated
…n warnings are generated
…n warnings are generated
…n warnings are generated
…be loaded due to a configuration mismatch with the current compilation fmtlib#4279
…be loaded due to a configuration mismatch with the current compilation fmtlib#4279
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This looks similar to #4580. In the future please update the PR instead of closing and creating a new one. |
OK, thank you for your suggestion. |
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Could you provide an example demonstrating the problem? |
It's ok, thank you for checking the code. |
…be loaded due to a configuration mismatch with the current compilation fmtlib#4279#4582
vitaut
requested changes
Oct 30, 2025
Comment on lines
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| # Decide whether to use CMake's FILE_SET-based module support. We only enable | ||
| # it when the generator and CMake version support it and the compiler is not | ||
| # GCC (GCC lacks import-graph discovery in many setups). This check must run | ||
| # after project() so CMAKE_CXX_COMPILER_ID is available. | ||
| if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.28 AND | ||
| CMAKE_GENERATOR STREQUAL "Ninja" AND | ||
| NOT CMAKE_CXX_COMPILER_ID MATCHES "GNU") | ||
| set(FMT_USE_CMAKE_MODULES TRUE) | ||
| else() | ||
| set(FMT_USE_CMAKE_MODULES FALSE) | ||
| endif() | ||
| message(STATUS "FMT_USE_CMAKE_MODULES = ${FMT_USE_CMAKE_MODULES}") |
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I think it's better not to split the logic to set FMT_USE_CMAKE_MODULES.
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[fix] error: module file CMakeFiles/__cmake_cxx23.dir/std.pcm cannot be loaded due to a configuration mismatch with the current compilation #4279
What I changed
The modifications I made (specific and traceable)
Edit file: CMakeLists.txt
In the manual pre-compilation module path (CMake does not use FILE_SET to manage modules), ensure that CMake's automatic module scanning is not triggered - to avoid build failures caused by CMake requiring the compiler to support import-graph scanning.
In scenarios where it is not safe to use CMake's FILE_SET module support (such as GCC + Ninja), FMT_USE_CMAKE_MODULES is disabled, causing the build to revert to manual pre-compilation/non-FILE_SET paths.
In environments where module support cannot be reliably provided (GCC's several versions), if the user requests -DFMT_MODULE=ON, FMT_MODULE will be automatically set back to OFF (and a warning will be printed) to avoid compiler internal errors (cc1plus segment errors) caused by -fmodules-ts.
In the manual module branch as the target, CXX_SCAN_FOR_MODULES (target property) is turned off, and CMAKE_CXX_SCAN_FOR_MODULES (cache) is globally turned off under GCC to ensure CMake no longer attempts to automatically scan.
Add diagnostic output to enable seeing the decision of FMT_USE_CMAKE_MODULES during configure (helpful for subsequent debugging).
(Notes) I did not modify the public API or source code functionality; only adjusted the CMake configuration logic, with minor and low-risk modifications.