Hi,
Hang on, you are saying that a *blocking* write(2) to a pipe returns
with EAGAIN? Are you sure? It would be quite a surprise if git would
actually do that. EAGAIN is only an expected error for non-blocking
I/O, so applications which use blocking I/O usually only test for EINTR.
I checked out the winsup sources and built a cygwin1.dll for debugging
(btw: Could you update the FAQ to state that gcc4 is required instead of
gcc?).
What I found out:
In fhandler.cc, write_overlapped, there is the call to WriteFile:
bool res = WriteFile (get_output_handle (), ptr, len, &nbytes,
get_overlapped ());
Surprisingly, this returns FALSE / nbytes = 0 / GetLastError =
ERROR_INVALID_HANDLE on WinXP if the number of bytes exceeds some
maximum and the handle refers to a pipe.
Since you don't know what kind of handle you're writing to in
write_overlapped, it seems reasonable to do the write in chunks.
The first comment to WriteFile
(http://msdn.microsoft.com/en-us/library/aa365747%28v=vs.85%29.aspx)
suggests to limit the size to less than 32MB per write - although I
didn't have this problem on X64.
-Robert
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