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Re: [PATCH] mingw: emulate write(2) that fails with a EPIPE

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
Dec 17, 2015, 09:37 UTC
Message-ID
<alpine.DEB.2.20.1512171035580.6483@virtualbox>
In-Reply-To
<CAPig+cQzCHtyVs47=ASs5V2BSV7gpVszbdTFydiRhnz3gtD2Qw@mail.gmail.com>
Hi Eric,
On Wed, 16 Dec 2015, Eric Sunshine wrote:
Show 22 quoted lines
> On Wednesday, December 16, 2015, Johannes Schindelin
> <johannes.schindelin@gmx.de> wrote:
> > diff --git a/compat/mingw.h b/compat/mingw.h
> > @@ -210,6 +210,24 @@ FILE *mingw_freopen (const char *filename, const char *otype, FILE *stream);
> > +static inline ssize_t mingw_write(int fd, const void *buf, size_t len)
> > +{
> > +       ssize_t result = write(fd, buf, len);
> > +
> > +       if (result < 0 && errno == EINVAL && buf) {
> 
> Here, errno is EINVAL...
> 
> > +               /* check if fd is a pipe */
> > +               HANDLE h = (HANDLE) _get_osfhandle(fd);
> > +               if (GetFileType(h) == FILE_TYPE_PIPE)
> > +                       errno = EPIPE;
> > +               else
> > +                       errno = EINVAL;
> 
> Does any of the code between the outer 'if' and this point clobber
> errno, or are you merely assigning EINVAL for robustness against
> future changes?

Yes, it is proofing the code against future changes. And TBH I did not even bother to check whether _get_osfhandle() or GetFileType() can modify the errno value, since I *really* wanted to make sure that errno is either EPIPE or EINVAL in this execution path.

Ciao, Dscho

Previous: Junio C HamanoNext: Johannes Schindelin
Message 8 of 13 in “mingw: emulate write(2) that fails with a EPIPE”
  1. mingw: emulate write(2) that fails with a EPIPEJohannes Schindelin, Dec 16, 2015
  2. Junio C HamanoDec 16, 2015
  3. Johannes SchindelinDec 17, 2015
  4. Junio C HamanoDec 17, 2015
  5. Johannes SchindelinDec 17, 2015
  6. Eric SunshineDec 16, 2015
  7. Junio C HamanoDec 16, 2015
  8. Johannes SchindelinDec 17, 2015
  9. mingw: emulate write(2) that fails with a EPIPEJohannes Schindelin, Dec 17, 2015
  10. Junio C HamanoDec 17, 2015
  11. Johannes SchindelinDec 18, 2015
  12. Johannes SixtDec 18, 2015
  13. Junio C HamanoDec 21, 2015

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