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Re: [Qemu-devel] [PATCH 01/14] Introduce qemu_write_full()
From: |
malc |
Subject: |
Re: [Qemu-devel] [PATCH 01/14] Introduce qemu_write_full() |
Date: |
Thu, 31 Dec 2009 14:47:05 +0300 (MSK) |
On Thu, 31 Dec 2009, Kirill A. Shutemov wrote:
> 2009/12/31 malc <address@hidden>:
> > On Thu, 31 Dec 2009, Kirill A. Shutemov wrote:
> >
> >> On Thu, Dec 31, 2009 at 4:00 AM, malc <address@hidden> wrote:
> >> > On Thu, 31 Dec 2009, Kirill A. Shutemov wrote:
> >> >
> >> >> A variant of write(2) which handles partial write.
> >> >>
> >> >> Signed-off-by: Kirill A. Shutemov <address@hidden>
> >> >> ---
> >> >> osdep.c | 27 +++++++++++++++++++++++++++
> >> >> qemu-common.h | 1 +
> >> >> 2 files changed, 28 insertions(+), 0 deletions(-)
> >> >>
> >> >> diff --git a/osdep.c b/osdep.c
> >> >> index e4836e7..d2406f2 100644
> >> >> --- a/osdep.c
> >> >> +++ b/osdep.c
> >> >> @@ -243,6 +243,33 @@ int qemu_open(const char *name, int flags, ...)
> >> >> return ret;
> >> >> }
> >> >>
> >> >> +/*
> >> >> + * A variant of write(2) which handles partial write.
> >> >> + *
> >> >> + * Return the number of bytes transferred.
> >> >> + * Set errno if fewer than `count' bytes are written.
> >> >> + */
> >> >> +ssize_t qemu_write_full(int fd, const void *buf, size_t count)
> >> >> +{
> >> >> + ssize_t ret = 0;
> >> >> + ssize_t total = 0;
> >> >> +
> >> >> + while (count) {
> >> >> + ret = write(fd, buf, count);
> >> >> + if (ret < 0) {
> >> >> + if (errno == EINTR)
> >> >> + continue;
> >> >> + break;
> >> >> + }
> >> >> +
> >> >> + count -= ret;
> >> >> + buf += ret;
> >> >> + total += ret;
> >> >> + }
> >> >> +
> >> >> + return total;
> >> >> +}
> >> >
> >> > This hides write errors.
> >>
> >> Why do you think so? Return value < count indicates error.
> >
> > It does not indicate _which_ error it was.
>
> ???
>
> You can check errno.
Uh, yes, sorry, been writing too much driver code lately.
Nitpick then, no reason to set ret to zero at the beginning of the
function.
--
mailto:address@hidden
Re: [Qemu-devel] [PATCH 01/14] Introduce qemu_write_full(), malc, 2009/12/30
[Qemu-devel] Re: [PATCH 01/14] Introduce qemu_write_full(), Paolo Bonzini, 2009/12/31