If I have a definition which is only repeated strings, I can find the length of the packed buffers via the get_packed_size call. However, if I am on the receiving side of the exchange, how do I know how many bytes to read to form a complete message? (Since there are a variable number of entries, it isn’t known apriori.)
Sender:
length = <name>_get_packed_size(&message)
buffer = malloc(length)
<name>_pack(&message, buffer)
write(fd, buffer, length)
Receiver:
read(fd, buffer, ???) // what is '???' if 'fd' is a stream socket?
If I am in datagram mode, I can issue the read for something like 64K bytes and just get the entire message. However, if I am in stream mode, how do I do this without short changing the message or reading part of the next message?
See this answer for a typical solution to this common problem: https://stackoverflow.com/a/5586945/618259