mingw-w64 + improve ddsrt_recvmsg interface #2053
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Signed-off-by: Erik Boasson <[email protected]>
There is only one caller of ddsrt_recvmsg (outside the tests), ddsi_udp_conn_read, and it assumed that ddsrt_recvmsg: 1. returns OK with *rcvd > 0 2. returns OK with *rcvd = 0 3. returns not-OK with *rcvd untouched or set to 0 Case 1 is the perfectly ordinary case. Case 2 is treated as a spurious but successful read. This is somewhat weird: the socket triggers because data is available and so a read should return something. IIRC it is there because with OpenSSL 3 and TCP+TLS I saw received bytes all getting consumed internally by OpenSSL during a handshake. Anyway, it exists. Case 3 is for all errors. The "*rcvd untouched or set to 0" was important because ddsi_udp_conn_read would first check whether it is > 0. It initializes it to 0, so if it is untouched on error or set to 0, all is well. The one caller of ddsi_udp_conn_read is ddsi_receive.c:do_packet, which simply ignores any call to ddsi_udp_conn_read that returns <= 0. So case 2 can be propagated by returning 0 (successful spurious read) or < 0 (error) without any difference in behaviour. This requirement on *rcvd in case of an error is an accident waiting to happen. This commit changes the interface so that it is: 1. OK and *rcvd >= 0 2. not-OK and *rcvd undefined This requires no changes on the implementation of ddsrt_recvmsg. The change in the caller is trivial and makes it as one would expect. Signed-off-by: Erik Boasson <[email protected]>
The CMSG_* macros used in CycloneDDS are not provided by mingw-w64-gcc (only WSA*). Signed-off-by: Erik Boasson <[email protected]>
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This takes the change for
PACKET_DESTINATION_INFOfrom #2045 and bundles it with an improvement to the interface ofddsrt_recvmsg.Closes #2027