Re: [Qemu-devel] [PATCH 01/14] Introduce qemu_write_full()

[Kirill A. Shutemov]

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.