Hi Mark, On Feb 9 02:50, Mark Geisert wrote: > Per discussion on cygwin-developers, a Cygwin tmpfile(3) implementation > has been added to syscalls.cc. This overrides the one supplied by > newlib. Then the open(2) flag O_TMPFILE was added to the open call that > tmpfile internally makes. > --- > winsup/cygwin/release/3.2.0 | 4 ++++ > winsup/cygwin/syscalls.cc | 20 ++++++++++++++++++++ > 2 files changed, 24 insertions(+) > > diff --git a/winsup/cygwin/release/3.2.0 b/winsup/cygwin/release/3.2.0 > index f748a9bc8..d02d16863 100644 > --- a/winsup/cygwin/release/3.2.0 > +++ b/winsup/cygwin/release/3.2.0 > @@ -19,6 +19,10 @@ What changed: > > - A few FAQ updates. > > +- Have tmpfile(3) make use of Win32 FILE_ATTRIBUTE_TEMPORARY via open(2) > + flag O_TMPFILE. > + Addresses: https://cygwin.com/pipermail/cygwin/2021-January/247304.html > + > > Bug Fixes > --------- > diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc > index 52a020f07..b79c1c7cd 100644 > --- a/winsup/cygwin/syscalls.cc > +++ b/winsup/cygwin/syscalls.cc > @@ -5225,3 +5225,23 @@ pipe2 (int filedes[2], int mode) > syscall_printf ("%R = pipe2([%d, %d], %y)", res, read, write, mode); > return res; > } > + > +extern "C" FILE * > +tmpfile (void) > +{ > + char *dir = getenv ("TMPDIR");
This isn't what Linux tmpfile does. Per the man page, it tries to create the file in P_tmpdir first, and if that fails, it tries "/tmp". > + if (!dir) > + dir = P_tmpdir; > + int fd = open (dir, O_RDWR | O_CREAT | O_BINARY | O_TMPFILE, You have to specify O_EXCL here. The idea is that this file cannot be made permanent, and missing the O_EXCL flag allows exactly that. See https://man7.org/linux/man-pages/man2/open.2.html, the lengthy description in terms of O_TMPFILE. Thanks, Corinna
