libsqlite3_sys::sqlite3_create_function

pub unsafe extern fn sqlite3_create_function(db: *mut sqlite3, zFunctionName: *const c_char, nArg: c_int, eTextRep: c_int, pApp: *mut c_void, xFunc: Option<extern fn(arg1: *mut sqlite3_context, arg2: c_int, arg3: *mut *mut sqlite3_value)>, xStep: Option<extern fn(arg1: *mut sqlite3_context, arg2: c_int, arg3: *mut *mut sqlite3_value)>, xFinal: Option<extern fn(arg1: *mut sqlite3_context)>) -> c_int