Differences between sendmessage and postmessage

I was asked during the interview today what is the difference between sendmessage and postmessage. I really don't know. The question is speechless. I checked it back and found it a little different.

Msdn mentioned

TheSendmessageMember function callthe window procedure directly and does not return until that window procedure has processed the message. This is in contrast toPostmessageMember function, which places the message into the window's message queue and returns immediately.

 

Sendmessage is the synchronous function. It not only sends messages to the message queue, but also needs to wait until the message is executed. On the contrary, postmessage is an asynchronous function, which only sends a message, no matter whether the message is processed or not, it will be returned immediately.