Symptom
When a HAP project is built, the compilation tool reports "error: unknown type name '_Bool'", which indicates that the _Bool type cannot be found.
Possible Causes
JSVM-API is based on C-API of the C99 standard. Pay attention to compatibility when using JSVM-API in C++ projects.
The default setting of Clang++ (the C++ compilation toolchain) provided by the current SDK version is -std=gnu++14. If -std=c++xx is specified, the default setting will be overwritten, and Clang specifies the compilation macros of strict ANSI, which correspond to C90 and does not include any GNU C extension. As a result, _Bool introduced by C99 cannot be found. The -std=gnu++xx option enables GNU C extension support and does not generate compilation errors.
Solution
Check whether the -std=c++xx series options (such as 11, 14, and 17) are added to the build options.
If yes, the following solutions can be used to solve this problem:
- If the C++ version is C++14 or earlier, you can remove the -std=c++xx option. The default configuration of the compilation toolchain provided by DevEco Studio is -std=gnu++14.
- If the C++ version must be specified, change -std=c++xx to -std=gnu++xx.
- You can also add the -U__STRICT_ANSI__ option to the CMakeLists.txt file to solve this problem.