Re: Can EINTR be handled the way BSD handles it? -- a plea from a user-land programmer...

[Ulrich Drepper <drepper@redhat.com>]

"Theodore Y. Ts'o" <tytso@MIT.EDU> writes:

> Arguably though the bug is in glibc, in that if it's using signals
> behinds the scenes, it should have passed SA_RESTART to sigaction.

Why are you talking  such a nonsense?

> 
> However, from a portability point of view, you should *always* surround
> certain system calls with while loops, since even if your program
> doesn't use signals, if you run that program on a System-V derived Unix
> system, and someone types ^Z at the wrong moment, you can also get an
> EINTR.   Similarly, you should always check the return value from write
> and make sure all of what you asked to be written, was actually
> written.
> 
> What I normally do is have a full_write routine which looks something
> like this:
> 
> static errcode_t full_write(int fd, void *buf, int count)
> {
> 	char	*cp = buf;
> 	int	left = count, c;
> 
> 	while (left) {
> 		c = write(fd, cp, left);
> 		if (c < 0) {
> 			if (errno == EINTR || errno == EAGAIN)
> 				continue;
> 			return errno;
> 		}
> 		left -= c;
> 		cp += c;
> 	}
> 	return 0;
> }
> 
> It's like checking the return value from malloc().  Not everyone does
> it, but even if it's not needed 99% of the time, it's a darned good idea
> to do that.
> 
> 					- Ted
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> 

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