void tuner_write_WBU8 tuner_command U8 tuner_length U8 length = 0; bit ack;bit ack;报错位变量必须是全局的或静态

To fix the error, you can declare the "ack" variable as a static variable within the function like this:

void tuner_write_WB(U8 tuner_command, U8 tuner_length)
{
    U8 length = 0;
    static bit ack;
}

By declaring it as static, the variable will retain its value between function calls and can be used in subsequent calls without being re-initialized.