Il 21/02/2013 17:47, Andy Wingo ha scritto:
>> > Doesn't it need to set errno to zero before calling full_read?
> Not sure! If full_read requires that errno be 0 going in, then yes, we
> should. Is this a requirement?
Hmm, I think usually errno is undefined for return values other than -1,
so neither approach would work portably...
I think you have to do
ret = full_read (fd, cookie, sizeof cookie);
if (ret < sizeof cookie && ret != -1)
ret = 0;
if (ret == sizeof cookie)
ret = full_read (fd, SCM_BYTEVECTOR_CONTENTS (bv),
SCM_BYTEVECTOR_LENGTH (bv));
if (ret < SCM_BYTEVECTOR_LENGTH (bv))
{
int errno_save = errno;
(void) close (fd);
errno = errno_save;
if (ret == -1)
SCM_SYSERROR;
scm_misc_error (FUNC_NAME, "file truncated while reading",
SCM_EOL);
}
Paolo
> Otherwise, full_read sets errno to 0 if it returns a length less than
> the length we asked for, and we're OK in that case AFAICS.
