diff --git a/libpldm/platform.h b/libpldm/platform.h
index 0ee050a..0d4ddde 100644
--- a/libpldm/platform.h
+++ b/libpldm/platform.h
@@ -682,7 +682,8 @@
  *        transferred
  *  @param[out] resp_cnt - The number of recordData bytes returned in this
  *        response
- *  @param[out] record_data - PDR data bytes of length resp_cnt
+ *  @param[out] record_data - PDR data bytes of length resp_cnt, or NULL to
+ *        skip the copy and place the actual length in resp_cnt.
  *  @param[in] record_data_length - Length of record_data
  *  @param[out] transfer_crc - A CRC-8 for the overall PDR. This is present only
  *        in the last part of a PDR being transferred