Hi Elliot, On 10/1/18 7:33 PM, enh wrote: > Since adding checking to Android's bionic for file descriptor double-closes, > we've found that the most common cause of these bugs is incorrect use of > fileno(3). There appears to be a common misconception that it transfers > ownership of the file descriptor to the caller. Thanks. Patch applied. Cheers, Michael > --- > man3/ferror.3 | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/man3/ferror.3 b/man3/ferror.3 > index b45eb5559..609e10cf8 100644 > --- a/man3/ferror.3 > +++ b/man3/ferror.3 > @@ -89,7 +89,15 @@ The function > .BR fileno () > examines the argument > .I stream > -and returns its integer file descriptor. > +and returns the integer file descriptor used to implement this stream. > +The file descriptor is still owned by > +.I stream > +and will be closed when > +.BR fclose (3) > +is called. > +Duplicate the file descriptor with > +.BR dup (2) > +before passing it to code that might close it. > .PP > For nonlocking counterparts, see > .BR unlocked_stdio (3). > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
