[nanomsg] Re: nn_sendmsg man page vs. source code

  • From: Martin Sustrik <sustrik@xxxxxxxxxx>
  • To: nanomsg@xxxxxxxxxxxxx
  • Date: Tue, 24 Sep 2013 10:55:14 +0200

Hi Zoltan,


I am reading the source of nanomsg and found some a little inconsistency.
in nn_sendmsg()
  from the man page.

1. Return value.

"Otherwise, negative number is returned and errno is set..."

The negative number is -1 in every case. It would be nice to says that
explicitly.
That's also true for other functions. It's always -1 rather than random negative number. 


2. Behaviour regarding the pre-allocated message buffer:

"Alternatively, to send a buffer allocated by nn_allocmsg(3) function
  set iov_base to point to the pointer to the buffer and iov_len to
NN_MSG constant.
  The buffer will be deallocated by nn_send function. Trying to
deallocate it afterwards
  will result in undefined behaviour. Also, scatter array in nn_msghdr
structure
  can contain only one element in this case."

The message buffer is *not* deallocated in case an error is returned early.
The values of errno where it's not deallocated are: EINVAL, EMSGSIZE,
EFAULT.


Yes, true.


These error values are not even documented in the man page.
Would you like to patch it? The documentation source is in /doc subdirectory in asciidoc (text-based) format. 

Martin

Other related posts:

  1. Home
  2. nanomsg
  3. Archive
  4. 09-2013