While building, bpftool makes a skeleton from test_core_extern.c, which itself includes <stdbool.h> and uses the 'bool' type. However, the skeleton test_core_extern.skel.h generated *does not* include <stdbool.h> or use the 'bool' type, instead using the C-only '_Bool' type. Compiling test_cpp.cpp with g++ 12.3 for mips64el/musl-libc then fails with error:
In file included from test_cpp.cpp:9: test_core_extern.skel.h:45:17: error: '_Bool' does not name a type 45 | _Bool CONFIG_BOOL; | ^~~~~
This was likely missed previously because glibc uses a GNU extension for <stdbool.h> with C++ (#define _Bool bool), not supported by musl libc.
Normally, a C fragment would include <stdbool.h> and use the 'bool' type, and thus cleanly work after import by C++. The ideal fix would be for 'bpftool gen skeleton' to output the correct type/include supporting C++, but in the meantime add a conditional define as above.
Fixes: 7c8dce4b1661 ("bpftool: Make skeleton C code compilable with C++ compiler") Signed-off-by: Tony Ambardar tony.ambardar@gmail.com --- tools/testing/selftests/bpf/test_cpp.cpp | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_cpp.cpp b/tools/testing/selftests/bpf/test_cpp.cpp index dde0bb16e782..abc2a56ab261 100644 --- a/tools/testing/selftests/bpf/test_cpp.cpp +++ b/tools/testing/selftests/bpf/test_cpp.cpp @@ -6,6 +6,10 @@ #include <bpf/libbpf.h> #include <bpf/bpf.h> #include <bpf/btf.h> + +#ifndef _Bool +#define _Bool bool +#endif #include "test_core_extern.skel.h" #include "struct_ops_module.skel.h"