(PHP 4, PHP 5, PHP 7, PHP 8)
imap_msgno — Gets the message sequence number for the given UID
$imap, int $message_uid): int
   Returns the message sequence number for the given 
   message_uid.
  
This function is the inverse of imap_uid().
imapAn IMAP\Connection instance.
message_uidThe message UID
   Returns the message sequence number for the given 
   message_uid.
  
| 版本 | 说明 | 
|---|---|
| 8.1.0 | The imapparameter expects an IMAP\Connection
  instance now; previously, a 资源(resource) was expected. |