Hmm, that casting problem in the original code snippet should be unrelated to embind.
This command line from the article forces all .c files to be compiled as C++ because of the "-x c++" command line option: emcc --bind -O3 --std=c++11 a_c_file.c another_c_file.c *-x c++* your_cpp_file.cpp So that's the problem. If you drop both the "-std=c++11" and "-x c++" command line options it should work, because then the .c files will be compiled as C and the .cpp files as C++. If you actually need to control the C++ version used via "-std=c++11", then I think you need to invoke emcc twice, once to compile all .c files, and another time to compile all .cpp files (maybe there's another way to do it in one invokation I'm not aware of though). Cheers! On Thursday, 8 July 2021 at 00:45:51 UTC+2 [email protected] wrote: > Thanks for taking a look. I must be doing something incorrectly. Here is > the article I am trying to follow. Note this section "What about C?" > https://developers.google.com/web/updates/2018/08/embind#what_about_c > > *embind was written for C++ and can only be used in C++ files, but that > doesn't mean that you can't link against C files! To mix C and C++, you > only need to separate your input files into two groups: One for C and one > for C++ files and augment the CLI flags for emcc as follows:* > *$ emcc --bind -O3 --std=c++11 a_c_file.c another_c_file.c -x c++ > your_cpp_file.cpp* > > I tried doing similar in my case where I replace the ".c" files with the > library I'm trying to bind, and I replace the ".cpp" file with my own > bindings file. > > Perhaps the included command is wrong? > > Cheers > Ben > > On Tuesday, July 6, 2021 at 6:46:57 AM UTC-4 Floh wrote: > >> This is weird because it looks the .c file is compiled as C++ (not >> requiring a cast for malloc() is perfectly fine C code, but not valid C++ >> code). >> >> I would start looking into the build system instead of trying to >> "C++-ify" the C sources. Somehow the build system seems to treat .c files >> as C++ (maybe it always calls em++ instead of emcc? emcc should select the >> right language mode based on the file extension, while em++ forces C++ mode >> even for .c files. >> >> As a "hack" you can also force compilation in C mode with the "-x c" >> command line option, for instance: >> >> em++ bla.c -o bla -x c >> >> On Monday, 5 July 2021 at 02:18:37 UTC+2 [email protected] wrote: >> >>> Apologies if this is less of an embind question and more of a "how does >>> interop work with C and C++" question. I"m a bit inexperienced using them >>> together but in my case I'm trying to use embind, which requires bindings >>> written in C++, and the library I want to link is written in C. When I try >>> to link this library (https://github.com/korginc/volcasample) I get an >>> error about implicit pointer type conversion: >>> >>> ../volcasample/syro/korg_syro_volcasample.c:713:23: error: assigning to >>> 'uint8_t *' (aka 'unsigned char *') from incompatible type 'void *' >>> psms[i].comp_buf = malloc(comp_dest_size + >>> comp_ofs); >>> ^ >>> >>> I suppose I could convert the library to valid C++ with correct casting >>> but I'm hoping to avoid having to patch the source library in order to link >>> it. Is there another way? A compiler flag to allow implicit pointer type >>> casting or something like that? >>> >>> Thanks >>> Ben >>> >> -- You received this message because you are subscribed to the Google Groups "emscripten-discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/emscripten-discuss/05fc2514-0db0-48a2-b6cb-3d9bb43c116bn%40googlegroups.com.
