(PHP 7 >= 7.4.0, PHP 8)
FFI::load — Loads C declarations from a C header file
   Loads C declarations from a C header file. It is possible to specify shared libraries that should be loaded,
   using special FFI_LIB defines in the loaded C header file.
  
filenameThe name of a C header file.
      C preprocessor directives are not supported, i.e. #include,
      #define and CPP macros do not work, except for special cases
      listed below.
     
      The header file should contain a #define statement for the
      FFI_SCOPE variable, e.g.: #define FFI_SCOPE "MYLIB".
      Refer to the class introduction for details.
     
      The header file may contain a #define statement for the
      FFI_LIB variable to specify the library it exposes. If it is
      a system library only the file name is required, e.g.: #define FFI_LIB
      "libc.so.6".  If it is a custom library, a relative path is required,
      e.g.: #define FFI_LIB "./mylib.so".