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