[Bug stdio/1190] fgetc()/fread() behaviour is not POSIX compliant

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=1190

--- Comment #18 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".

The branch, master has been updated
       via  2cc7bad0ae0a412e75270be5ed41d45c03e7a931 (commit)
      from  778f1974863d63e858b6d0105e41d6f0c30732d3 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.

- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=2cc7bad0ae0a412e75270be5ed41d45c03e7a931

commit 2cc7bad0ae0a412e75270be5ed41d45c03e7a931
Author: Zack Weinberg <zackw@panix.com>
Date:   Wed Feb 21 19:12:51 2018 -0500

    [BZ 1190] Make EOF sticky in stdio.

    C99 specifies that the EOF condition on a file is "sticky": once EOF
    has been encountered, all subsequent reads should continue to return
    EOF until the file is closed or something clears the "end-of-file
    indicator" (e.g. fseek, clearerr).  This is arguably a change from
    C89, where the wording was ambiguous; the BSDs always had sticky EOF,
    but the System V lineage would attempt to read from the underlying fd
    again.  GNU libc has followed System V for as long as we've been
    using libio, but nowadays C99 conformance and BSD compatibility are
    more important than System V compatibility.

    You might wonder if changing the _underflow impls is sufficient to
    apply the C99 semantics to all of the many stdio functions that
    perform input.  It should be enough to cover all paths to _IO_SYSREAD,
    and the only other functions that call _IO_SYSREAD are the _seekoff
    impls, which is OK because seeking clears EOF, and the _xsgetn impls,
    which, as far as I can tell, are unused within glibc.

    The test programs in this patch use a pseudoterminal to set up the
    necessary conditions.  To facilitate this I added a new test-support
    function that sets up a pair of pty file descriptors for you; it's
    almost the same as BSD openpty, the only differences are that it
    allocates the optionally-returned tty pathname with malloc, and that
    it crashes if anything goes wrong.

        [BZ #1190]
            [BZ #19476]
        * libio/fileops.c (_IO_new_file_underflow): Return EOF immediately
        if the _IO_EOF_SEEN bit is already set; update commentary.
        * libio/oldfileops.c (_IO_old_file_underflow): Likewise.
        * libio/wfileops.c (_IO_wfile_underflow): Likewise.

        * support/support_openpty.c, support/tty.h: New files.
        * support/Makefile (libsupport-routines): Add support_openpty.

        * libio/tst-fgetc-after-eof.c, wcsmbs/test-fgetwc-after-eof.c:
        New test cases.
        * libio/Makefile (tests): Add tst-fgetc-after-eof.
        * wcsmbs/Makefile (tests): Add tst-fgetwc-after-eof.

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                     |   17 ++++++
 NEWS                          |    8 +++
 libio/Makefile                |    3 +-
 libio/fileops.c               |    7 +--
 libio/oldfileops.c            |    7 +--
 libio/tst-fgetc-after-eof.c   |  109 +++++++++++++++++++++++++++++++++++++++
 libio/wfileops.c              |    4 ++
 support/Makefile              |    1 +
 support/support_openpty.c     |  109 +++++++++++++++++++++++++++++++++++++++
 support/tty.h                 |   45 ++++++++++++++++
 wcsmbs/Makefile               |    2 +-
 wcsmbs/tst-fgetwc-after-eof.c |  114 +++++++++++++++++++++++++++++++++++++++++
 12 files changed, 416 insertions(+), 10 deletions(-)
 create mode 100644 libio/tst-fgetc-after-eof.c
 create mode 100644 support/support_openpty.c
 create mode 100644 support/tty.h
 create mode 100644 wcsmbs/tst-fgetwc-after-eof.c

-- 
You are receiving this mail because:
You are on the CC list for the bug.