diff options
Diffstat (limited to 'pcap.3pcap.in')
| -rw-r--r-- | pcap.3pcap.in | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/pcap.3pcap.in b/pcap.3pcap.in index f5a7e0ca..85a2f5b3 100644 --- a/pcap.3pcap.in +++ b/pcap.3pcap.in @@ -580,7 +580,9 @@ for packets to become available. On some, but all, platforms, if a read timeout was specified, the wait will terminate after the read timeout expires; applications should be prepared for this, as it happens on some platforms, but should not rely on it, as it -does not happen on other platforms. +does not happen on other platforms. Note that the wait might, or might +not, terminate even if no packets are available; applications should be +prepared for this to happen, but must not rely on it happening. .PP A handle can be put into ``non-blocking mode'', so that those routines will, rather than blocking, return an indication that no packets are @@ -596,8 +598,8 @@ Non-blocking mode is often combined with routines such as .BR select (2) or .BR poll (2) -or other routines a platform offers to wait for the availability of data -on any of a set of descriptors. To obtain, for a handle, a descriptor +or other routines a platform offers to wait for any of a set of +descriptors to be ready to read. To obtain, for a handle, a descriptor that can be used in those routines, call .BR pcap_get_selectable_fd (). Not all handles have such a descriptor available; @@ -606,7 +608,14 @@ will return \-1 if no such descriptor exists. In addition, for various reasons, one or more of those routines will not work properly with the descriptor; the documentation for .BR pcap_get_selectable_fd () -gives details. +gives details. Note that, just as an attempt to read packets from a +.B pcap_t +may not return any packets if the read timeout expires, a +.BR select (), +.BR poll (), +or other such call may, if the read timeout expires, indicate that a +descriptor is ready to read even if there are no packets available to +read. .TP .B Routines .RS |