Re: [lwip-users] Detect RST when using non blocking read.

[Gisle Vanem]

"Karlsson, Johnny" <address@hidden> wrote:

> Ok, that seems much better. But one more question .. You write that
> there is a global variable 'errno', but isn't there one errno variable
> for each socket? 

Normally there should be no need for that since 'errno' should
only be checked immediately after any socket (or system) function fails
(returning '< 0' normally). 'errno' is undefined at other times. 

But in the case your OS or application is multithreaded, 'errno' should 
return correct value for the thread in question. Otherwise a race condition 
occurs. The definition of 'errno' (a macro on Windows) should consider this.

E.g. for Coldfire:

#define errno (*sys_arch_errno())
...

int *sys_arch_errno(void)
{
   struct sys_thread *thread;
   thread = current_thread();
   return &thread->errno_i;
}

--gv