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| -rw-r--r-- | docs/KNOWN_BUGS | 60 |
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diff --git a/docs/KNOWN_BUGS b/docs/KNOWN_BUGS index 3e054f1bc..31e39fe3f 100644 --- a/docs/KNOWN_BUGS +++ b/docs/KNOWN_BUGS @@ -14,3 +14,63 @@ may have been fixed since this was written! * libcurl does not deal nicely with files larger than 2GB * GOPHER transfers seem broken + +------------------------------------------------------------------------------ + +Q: My program blows up when I run lots of curl_easy_perform() calls on a +single thread +Q: My program dies when a single thread re-enters the win32 select() call +via curl_easy_perform() +Q: --- add your own flavour here --- + +Single Threaded Re-Entracy +-------------------------- + +There is a glitch / trick to using cURL on Win32 related to re-entrancy. +This experience was gained on verion 7.9.4 using Windows NT SP3 in a banking +environment (just in case you wanted to know). + +If you have already called curl_easy_perform(), and *somehow* you cause your +single thread of execution to make another call to curl_easy_perform() - the +windows socket() call used to create a new socket for the second connection +can return with 10044 / 10043 error codes. + +The WSA errors we experienced are: +WSAEPROTONOSUPPORT +(10043) +Protocol not supported. +The requested protocol has not been configured into the system, or no +implementation for it exists. For example, a socket call requests a +SOCK_DGRAM socket, but specifies a stream protocol. + +WSAESOCKTNOSUPPORT +(10044) +Socket type not supported. +The support for the specified socket type does not exist in this address +family. For example, the optional type SOCK_RAW might be selected in a +socket call, and the implementation does not support SOCK_RAW sockets at +all. + +We have experienced this by creating a timer that ticks every 20ms, and on +the tick making a curl_easy_perform() call. The call usually completed in +about 300ms. And we expected (before this test) that the timer would NOT be +fired during a call to curl_easy_perform(), howvever, while the first +curl_easy_perform() is running a tick *is* fired by the windows API somehow, +and we then call curl_easy_perform() again - thus single threaded +re-entrancy is achieved. + +Notes: +* We made sure that a new CURL structure was being used for each +curl_easy_perform() request, and that the curl_global_init() had been called +beforehand. +* I'm happy to answer any questions about this problem to try to track it +down. +* Once the socket() call started failing, there is no hope - it never works +again. +* Slowing the timer down to give each request enough time to complete solves +this problem completely. + +If anyone has the source code to the WinNT implementation of socket() and +can figure out WHY this can occur, more tracing can be performed. + + John Clayton <John.Clayton at barclayscapital.com> |