In doing some testing on the project I'm working on I came
across something that is causing a bit of confusion on my part.
According to readv(2) EINVAL is returned for an invalid
argument. The examples given were count might be greater than
MAX_IOVEC or zero. The test case I am working with has count = 0
and I get return of 0 and errno 0 instead of the expected -1
and errno EINVAL.
Am I missing something?
Thanks!
Jim Hollenback
On Fri, Mar 15, 2002 at 01:54:26PM -0800, Jim Hollenback wrote:
> In doing some testing on the project I'm working on I came
> across something that is causing a bit of confusion on my part.
>
> According to readv(2) EINVAL is returned for an invalid
> argument. The examples given were count might be greater than
> MAX_IOVEC or zero. The test case I am working with has count = 0
> and I get return of 0 and errno 0 instead of the expected -1
> and errno EINVAL.
>
> Am I missing something?
http://www.opengroup.org/onlinepubs/007904975/
"The Open Group Base Specifications Issue 6", IEEE Std 1003.1-2001:
The readv() function may fail if:
[EINVAL]
The iovcnt argument was less than or equal to 0, or greater than {IOV_MAX}.
Notice the "may"? From the same document:
may
Describes a feature or behavior that is optional for an implementation
that conforms to IEEE Std 1003.1-2001. An application should not rely on
the existence of the feature or behavior. An application that relies on
such a feature or behavior cannot be assured to be portable across
conforming implementations.
To avoid ambiguity, the opposite of may is expressed as need not,
instead of may not.
So the 0 there just mean nothing, exactly what you get.
-alex