pub unsafe extern "C" fn vips_call_required_optional(
operation: *mut *mut VipsOperation,
required: *mut __va_list_tag,
optional: *mut __va_list_tag,
) -> c_intpub unsafe extern "C" fn vips_call_required_optional(
operation: *mut *mut VipsOperation,
required: *mut __va_list_tag,
optional: *mut __va_list_tag,
) -> c_int