Can someone explain why wineserver passes it's UNIX stdin/out/err fd's to a
running wine program by socket-based FD transfer every time a wine application
wants to do an operation on it's idea of stdin/out/err?
This has some annoying effects:
* It's very difficult to redirect stdin/out/err on wine applications.
* The appropriate FD is passed _every_ time such an operation is issued (so if
a lot of lines are being printed to stderr, say, a sendmsg/recvmsg pair is
issued for every line).
* It costs a small fortune in context switches and message passing overhead.
To see what I mean, take a look at this "strace wine -- cl -?" excerpt...
write(3, "&\0\0\0", 4) = 4
recvmsg(3, {msg_name(0)=NULL, msg_iov(1)=[{"\0\0\0\0", 4}], msg_controllen=16,
msg_control=0x406f68a4, , msg_flags=0}, 0) = 4
write(6, "\r\n", 2) = 2
close(6) = 0
write(3, "&\0\0\0", 4) = 4
recvmsg(3, {msg_name(0)=NULL, msg_iov(1)=[{"\0\0\0\0", 4}], msg_controllen=16,
msg_control=0x406f68a4, , msg_flags=0}, 0) = 4
write(6, " "..., 44) = 44
close(6) = 0
write(3, "&\0\0\0", 4) = 4
recvmsg(3, {msg_name(0)=NULL, msg_iov(1)=[{"\0\0\0\0", 4}], msg_controllen=16,
msg_control=0x406f68a4, , msg_flags=0}, 0) = 4
write(6, "\r\n", 2) = 2
close(6) = 0
write(3, "&\0\0\0", 4) = 4
recvmsg(3, {msg_name(0)=NULL, msg_iov(1)=[{"\0\0\0\0", 4}], msg_controllen=16,
msg_control=0x406f68a0, , msg_flags=0}, 0) = 4
write(6, "(press <return> to continue)", 28) = 28
close(6) = 0
Every time it wants to write a line, it goes to wineserver (fd 3) and asks to
be sent a fd for stderr (fd 6).
David Howells
