# CMake 4.2.1 Detecting C compiler ABI info - failed

**URL:** https://discourse.cmake.org/t/cmake-4-2-1-detecting-c-compiler-abi-info-failed/15790
**Category:** Usage
**Created:** [August 17, 2026, 6:57pm UTC](https://discourse.cmake.org/t/cmake-4-2-1-detecting-c-compiler-abi-info-failed/15790 "2026-08-17T18:57:34Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![lostbits](https://discourse.cmake.org/letter_avatar_proxy/v4/letter/l/58956e/32.png) [@lostbits](https://discourse.cmake.org/u/lostbits)
#### Post date: [August 17, 2026, 6:57pm UTC](https://discourse.cmake.org/t/cmake-4-2-1-detecting-c-compiler-abi-info-failed/15790/1 "2026-08-17T18:57:34Z")

</div>

`Win11 Pro (x86-64)`  
`cygwin 3.7.1`  
`cmake 4.2.1`  
`gcc 17.0.0`

IN the first example of the cmake tutorial fails with the error above and as a result code to generate a target is not generated:

gmake[2]: \*\*\* No rule to make target ‘/d/home/skidmarks/Projects/Test/cmake/src/HelloWorld.cpp’, needed by ‘CMakeFiles/hello.dir/HelloWorld.cpp.o’. Stop.  
gmake[1]: \*\*\* [CMakeFiles/Makefile2:87: CMakeFiles/hello.dir/all] Error 2  
gmake: \*\*\* [Makefile:91: all] Error 2

It works on my desktop (same environment). The CMakeError log file is missing (from messages on stackoverlow and [discourse.cmake.org](http://discourse.cmake.org)), and I don’t know how to track down and fix my mistake. The cygwin path `(> echo $PATH | tr ':' '\n')` seems correct, and all compiles done with gcc/g++ outside of cmake work correctly. Both the C and C++ compilers are detected by cmake. But it fails for both the C/C++ checks on the ABI issue. Any idea how I can track down what in my environment is causing this failure?

The output of `> cmake -Bbuild .` is:

`-- The C compiler identification is GNU 17.0.0`  
`-- The CXX compiler identification is GNU 17.0.0`  
`-- Detecting C compiler ABI info`  
`-- Detecting C compiler ABI info - failed`  
`-- Check for working C compiler: /usr/bin/cc`  
`-- Check for working C compiler: /usr/bin/cc - works`  
`-- Detecting C compile features`  
`-- Detecting C compile features - done`  
`-- Detecting CXX compiler ABI info`  
`-- Detecting CXX compiler ABI info - failed`  
`-- Check for working CXX compiler: /usr/bin/c++.exe`  
`-- Check for working CXX compiler: /usr/bin/c++.exe - works`  
`-- Detecting CXX compile features`  
`-- Detecting CXX compile features - done`  
`-- Configuring done (5.3s)`  
`-- Generating done (0.1s)`  
`-- Build files have been written to: /d/home/skidmarks/Projects/Test/cmake/src/build`

There are two areas which may be problematic. In cygwin, /usr/bin/cc is a symbolic link, /usr/bin/cc → gcc.exe and /usr/bin/c++ is an executable file (/usr/bin/c++.exe). I have to check this on my desktop but I believe it’s the same. So, the executables are found but the ABI can not be verified.