poll返回有數(shù)據(jù)可讀但是讀不出數(shù)據(jù)于是程序陷入死循環(huán)

flynetcn

recvfrom(8, "", 1, MSG_PEEK, NULL, NULL) = 0
select(9, [8], [], [], {5, 0})          = 1 (in [8], left {4, 999998})
recvfrom(8, "", 4, 0, NULL, NULL)       = 0
poll([{fd=8, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 0) = 1 ([{fd=8, revents=POLLIN}])
recvfrom(8, "", 1, MSG_PEEK, NULL, NULL) = 0
select(9, [8], [], [], {5, 0})          = 1 (in [8], left {4, 999998})
recvfrom(8, "", 4, 0, NULL, NULL)       = 0
poll([{fd=8, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 0) = 1 ([{fd=8, revents=POLLIN}])
recvfrom(8, "", 1, MSG_PEEK, NULL, NULL) = 0
select(9, [8], [], [], {5, 0})          = 1 (in [8], left {4, 999998})
recvfrom(8, "", 4, 0, NULL, NULL)       = 0
poll([{fd=8, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 0) = 1 ([{fd=8, revents=POLLIN}])
recvfrom(8, "", 1, MSG_PEEK, NULL, NULL) = 0
select(9, [8], [], [], {5, 0})          = 1 (in [8], left {4, 999998})
recvfrom(8, "", 4, 0, NULL, NULL)       = 0
poll([{fd=8, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 0) = 1 ([{fd=8, revents=POLLIN}])
recvfrom(8, "", 1, MSG_PEEK, NULL, NULL) = 0
select(9, [8], [], [], {5, 0})          = 1 (in [8], left {4, 999998})
recvfrom(8, "", 4, 0, NULL, NULL)       = 0
poll([{fd=8, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 0) = 1 ([{fd=8, revents=POLLIN}])
recvfrom(8, "", 1, MSG_PEEK, NULL, NULL) = 0
select(9, [8], [], [], {5, 0})          = 1 (in [8], left {4, 999998})
recvfrom(8, "", 4, 0, NULL, NULL)       = 0

hnwyllmm

If no messages are available to be received and the peer has performed an orderly shutdown, recvfrom() shall return 0.
recvfrom 返回0是這個解釋

flynetcn

回復 2# hnwyllmm

謝謝，可能是第二種情況，訪問量多，半開連接多，斷開連接的時間長。