C++ support

cheadergen is, as of today, a C header generator. C++ projects can still consume cheadergen’s output, but only as C header(s) included from C++, not as a native C++ header with C++-idiomatic features.

What works today: --cpp-compat

The CLI flag is --cpp-compat (equivalently, [c].cpp_compat = true in cheadergen.toml). It tells cheadergen to wrap function and static declarations in an extern "C" block guarded by #ifdef __cplusplus:

#ifdef __cplusplus
extern "C" {
#endif // __cplusplus

double distance(Point a, Point b);

#ifdef __cplusplus
}  // extern "C"
#endif  // __cplusplus

That single addition is enough to make the generated .h file safe to #include from C++ source code. The C++ compiler now knows the declarations inside use the C calling convention and C name mangling (none), so linking against your Rust library “just works.”

The same header is still valid C: the #ifdef guards mean a C compiler sees the declarations directly.

What’s not (yet) supported: native C++ output

cheadergen cannot produce .hpp files with C++-idiomatic constructs (e.g. enum class, namespaces, templates, destructors, etc.).

Native C++ support is a feature gap and may be addressed in a future release. There is no scheduled timeline; if you’re interested in it, the issue tracker is the right place to express the use case or contribute.

In the meantime, --cpp-compat is the recommended path for any project that needs to consume cheadergen output from C++.

See also

• Limitations for a wider view of what cheadergen does and doesn’t do today.
• Anatomy of a generated header for where the extern "C" block lands in the generated file.
• Comparison with cbindgen. cbindgen does ship some C++-idiomatic features that cheadergen doesn’t.