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FAQ: mention that the network connection can be monitored

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Also note the prohibition on sharing handles across threads.
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Dan Fandrich 2013-04-15 22:26:18 +02:00
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@ -728,7 +728,7 @@ FAQ
When passing on a URL to curl to use, it may respond that the particular When passing on a URL to curl to use, it may respond that the particular
protocol is not supported or disabled. The particular way this error message protocol is not supported or disabled. The particular way this error message
is phrased is because curl doesn't make a distinction internally of whether is phrased is because curl doesn't make a distinction internally of whether
a particular protocol is not supported (ie never got any code added that a particular protocol is not supported (i.e. never got any code added that
knows how to speak that protocol) or if it was explicitly disabled. curl can knows how to speak that protocol) or if it was explicitly disabled. curl can
be built to only support a given set of protocols, and the rest would then be built to only support a given set of protocols, and the rest would then
be disabled or not supported. be disabled or not supported.
@ -1055,11 +1055,11 @@ FAQ
4.19 Why doesn't cURL return an error when the network cable is unplugged? 4.19 Why doesn't cURL return an error when the network cable is unplugged?
Unplugging the cable is not an error situation. The TCP/IP protocol stack Unplugging a cable is not an error situation. The TCP/IP protocol stack
was designed to be fault tolerant, so even though there may be a physical was designed to be fault tolerant, so even though there may be a physical
break somewhere the connection shouldn't be affected, just possibly break somewhere the connection shouldn't be affected, just possibly
delayed. Eventually, the physical break will be fixed or the data will be delayed. Eventually, the physical break will be fixed or the data will be
re-routed around the physical problem. re-routed around the physical problem through another path.
In such cases, the TCP/IP stack is responsible for detecting when the In such cases, the TCP/IP stack is responsible for detecting when the
network connection is irrevocably lost. Since with some protocols it is network connection is irrevocably lost. Since with some protocols it is
@ -1077,6 +1077,12 @@ FAQ
falls too low, and --connect-timeout and --max-time can be used to put an falls too low, and --connect-timeout and --max-time can be used to put an
overall timeout on the connection phase or the entire transfer. overall timeout on the connection phase or the entire transfer.
A libcurl-using application running in a known physical environment (e.g.
an embedded device with only a single network connection) may want to act
immediately if its lone network connection goes down. That can be achieved
by having the application monitor the network connection on its own using an
OS-specific mechanism, then signalling libcurl to abort (see also item 5.13).
5. libcurl Issues 5. libcurl Issues
@ -1086,7 +1092,9 @@ FAQ
We have written the libcurl code specifically adjusted for multi-threaded We have written the libcurl code specifically adjusted for multi-threaded
programs. libcurl will use thread-safe functions instead of non-safe ones if programs. libcurl will use thread-safe functions instead of non-safe ones if
your system has such. your system has such. Note that you must never share the same handle in
multiple threads.
If you use a OpenSSL-powered libcurl in a multi-threaded environment, you If you use a OpenSSL-powered libcurl in a multi-threaded environment, you
need to provide one or two locking functions: need to provide one or two locking functions: