On Mon, Aug 03, 2015 at 07:26:30PM +0200, Michael Niedermayer wrote: > On Mon, Aug 03, 2015 at 05:21:58PM +0200, Nicolas George wrote: > > Le sextidi 16 thermidor, an CCXXIII, Hendrik Leppkes a écrit : > > > The FILE struct is opaque in MSVC 2015, and the members of this struct > > > were never meant to be accessed in any case. > > > > > > No conditions are known where this check was needed to get characters > > > from stdin. > > > --- > > > > > > If someone does know which particular purpose this check serves, please > > > do let me know, and I'll be more than willing to find a solution which > > > does not involve accessing private/undocumented APIs. > > > > The offending commit is this one: > > > > http://git.videolan.org/?p=ffmpeg.git;a=commit;h=ca4d71b149ebe32aeaf617ffccf362624b9aafb1 > > > > It says "Based on code by Rolf Siegrist". > > > > My guess is: the test serves if other parts of the program already did read > > from stdin using the stdio API: peek in the sdtdio buffer before reading > > from the actual file descriptor. > > > > Since in FFmpeg nothing else reads from stdin, this should not be needed. > > > > Knowing where Rolf Siegrist's code was taken from exactly would help to make > > sure. > > i looked in my inbox and i found the patch but not the corresponding > prior communication that it seems to refer to ... > > This seems to have been related to some usecase like this: > > echo 'Call 5 reinit > fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf:text=HalloWold:fontcolor=white' > |./ffmpeg -vf > drawtext='fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf:text=TEst:fontcolor=white' > -i matrixbench_mpeg2.mpg -y out2999.avi > > does this help ?
i also found this comment in a patch in my inbox:
+ /* When using Standard C input functions, also check if there
+ is anything in the buffer. After a call to such functions,
+ the input waiting in the pipe will be copied to the buffer,
+ and the call to PeekNamedPipe can indicate no input available.
+ Setting stdin to unbuffered was not enough, IIRC */
+ if (stdin->_cnt > 0)
+ {
+ char ch;
+ //Read it
+ read(0, &ch, 1);
+ return ch;
+ }
This seems to explain what the code was intended to do
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Democracy is the form of government in which you can choose your dictator
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