Dim mailmes[44444] As Byte
Dim add[444] As Byte
Dim taitle[444] As Byte
Dim body[4444] As Byte

lstrcpy(add, "aaa@bbb.ccc")
lstrcpy(taitle, "[重要]至急連絡ください")
lstrcpy(body, "5万円")
wsprintf(mailmes, "mailto:%s?subject=%s&body=%s", add, taitle, body)
ShellExecute( 0, "open", mailmes, 0, 0, SW_SHOW)