Perl's open is equivalent to C's fopen and Perl's sysopen is equivalent to C's open.

I'm not very familiar with C. So, I have to ask... in which situation is open better than sysopen or vice-versa?

At a command prompt type perldoc -f sysopen and perldoc -f open. Or compare them on http://perldoc.perl.org/index-functions.html.

My summary is that sysopen is a lower-level interface that can't ever be removed because of backwards compatibility, while open is the one that I would suggest people use.

Not so. Both create buffered handles like fopen(3), not mere file descriptors like open(2)

The difference is the args you can pass to them.

That's not complete. Perl's open is equivalent to the union of C's fopen and popen.

Hi,
something like

unless (-e $file) {
        open(FH,">", "$file") or die $!;
}
[download]

is almost always wrong as it's open to race conditions.

So you're better off avoiding file tests:

use Fcntl;
# Open $file for writing unless it already exists
sysopen(FH, $file, O_WRONLY|O_EXCL|O_CREAT) or die $!;
[download]

HTH,
Thomas

Why do you want to have a file that you know you just created? Most of the time when I want that I really want File::Temp. For locking you have other options available, including flock. You can complain that flock often doesn't work well over networked file systems. But sysopen also doesn't work well on those systems.

So yes, there is a task that you can do with sysopen that you can't with open. But I have yet to encounter a situation where I thought that sysopen was the best option.

...from reading man pages you only learn, but you don't get XP :)

I'm not here to get XP, but for the learning. There's no point in earning XP if I'm not learning, what will I do with it? :)

I did read the perlopentut and man pages for open and sysopen. And as jwkrahn mentioned, sysopen is equivalent to C's open, but I'm still not sure what situation is open better than sysopen.

That depends on your definition of better. Some people consider less typing for common situation to be better. Further more, there are things that can be done with open that cannot be done with sysopen. And there things that can be done with sysopen that cannot be done with open.

Interestingly, none of those talk about the return values for sysopen. I'm going to guess that a falsey value is a fail.

obviously, rou read different documentation than I. All three (open, sysopen and perlopentut) explicitly say that undef is returned on failure, which is, as you 'guessed', a falsey value.

Edit: added the words in italics