You shouldn't be using ioctl in perl. If your structure and C's disagree even slightly, then weird things can happen. If your structure and perl's completely agree, weird things can still happen. There may be memory alignment considerations and the like which rearrange or misalign the members from the arrangement you expected, only the C compiler's judgement should be trusted on that.
I seem to remember 'struct flock''s arrangement does seem to be different in OSX than in Linux, too. Something about one of the types involved not actually being an integer anymore.
Fortunately, perl has a built-in flock function so you don't need to call ioctl yourself. It's not even a module, it comes with standard perl.
Code:
$ perldoc -f flock
flock FILEHANDLE,OPERATION
Calls flock(2), or an emulation of it, on FILEHANDLE. Returns
true for success, false on failure. Produces a fatal error if
used on a machine that doesn't implement flock(2), fcntl(2)
locking, or lockf(3). "flock" is Perl's portable file locking
interface, although it locks only entire files, not records.
Two potentially non-obvious but traditional "flock" semantics
are that it waits indefinitely until the lock is granted, and
that its locks merely advisory. Such discretionary locks are
more flexible, but offer fewer guarantees. This means that
programs that do not also use "flock" may modify files locked
with "flock". See perlport, your port's specific documenta-
tion, or your system-specific local manpages for details. It's
best to assume traditional behavior if you're writing portable
programs. (But if you're not, you should as always feel per-
fectly free to write for your own system's idiosyncrasies
(sometimes called "features"). Slavish adherence to portabil-
ity concerns shouldn't get in the way of your getting your job
done.)
OPERATION is one of LOCK_SH, LOCK_EX, or LOCK_UN, possibly com-
bined with LOCK_NB. These constants are traditionally valued
1, 2, 8 and 4, but you can use the symbolic names if you import
them from the Fcntl module, either individually, or as a group
using the ':flock' tag. LOCK_SH requests a shared lock,
LOCK_EX requests an exclusive lock, and LOCK_UN releases a pre-
viously requested lock. If LOCK_NB is bitwise-or'ed with
LOCK_SH or LOCK_EX then "flock" will return immediately rather
than blocking waiting for the lock (check the return status to
see if you got it).
To avoid the possibility of miscoordination, Perl now flushes
FILEHANDLE before locking or unlocking it.
Note that the emulation built with lockf(3) doesn't provide
shared locks, and it requires that FILEHANDLE be open with
write intent. These are the semantics that lockf(3) imple-
ments. Most if not all systems implement lockf(3) in terms of
fcntl(2) locking, though, so the differing semantics shouldn't
bite too many people.
...
Last edited by Corona688; 11-30-2011 at 03:29 PM..
Please help if you are familiar with Mac OSX. I downloaded OpenSSH for a newer version of SSH than what comes with OS 10.1. What a mistake! Now every time I try to make a connection to my remote server I get an message that ssh was built against version such and such and I have version such and... (2 Replies)
I finally broke down and decided to buy a new piece of hardware. I think I made the right decision when I chose an Apple iBook - OSX is incredible! I haven't used a Mac since System7.5, and 10.2 is just blowing me away!
Best of all, it's easy to use for people who are not used to Mac, but if I... (5 Replies)
I'm currently looking for an emulation program that would allow me to open and run osx app.s and programs on a windows xp based system.
if not is there a unix/linux/lindows program that may do the same? (3 Replies)
Hello,
I am trying to write a simple program with functions in the ncurses library, on a Mac running OSX 10.2.8, with the compiler and libraries that were included in the Dec 2002 Developer's tools release (the last one that runs on Jaguar, as far as I know). When I try to compile, I get... (2 Replies)
Hi,
I have installed bash 3.2 via darwin ports, however when I try and change the shell i.e. chsh -s /opt/local/bin/bash is says its a non-standard shell? but if i run ./bash i get a new bash prompt with version 3.2?
Thanks (3 Replies)
I've got this problem. My computers and external hard drives are converting many of my files to a Unix Executable File which has a grey terminal looking icon. I don't understand what is causing this to happen. It is happening to a large number of my image file of different formats and also... (1 Reply)
Hi,
Unless I am missing some serious differences in Mac and linux in terms of C programming, I dont know why this would happen. Please take a look at the following piece of code fragment:
bool add_input_to_db(Cons *new_data) {
// Set the attributes of the lock
struct flock fl =... (3 Replies)
Hey guyz,
Is it possible to build user-mode linux kernel on MAC OSX?
Please I need a reply asap as I have an assignment that I need to do.
Thanks!
Adel (1 Reply)
Discussion started by: aje02
1 Replies
LEARN ABOUT MOJAVE
file::spec::functions
File::Spec::Functions(3pm) Perl Programmers Reference Guide File::Spec::Functions(3pm)NAME
File::Spec::Functions - portably perform operations on file names
SYNOPSIS
use File::Spec::Functions;
$x = catfile('a','b');
DESCRIPTION
This module exports convenience functions for all of the class methods provided by File::Spec.
For a reference of available functions, please consult File::Spec::Unix, which contains the entire set, and which is inherited by the
modules for other platforms. For further information, please see File::Spec::Mac, File::Spec::OS2, File::Spec::Win32, or File::Spec::VMS.
Exports
The following functions are exported by default.
canonpath
catdir
catfile
curdir
rootdir
updir
no_upwards
file_name_is_absolute
path
The following functions are exported only by request.
devnull
tmpdir
splitpath
splitdir
catpath
abs2rel
rel2abs
case_tolerant
All the functions may be imported using the ":ALL" tag.
COPYRIGHT
Copyright (c) 2004 by the Perl 5 Porters. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
SEE ALSO
File::Spec, File::Spec::Unix, File::Spec::Mac, File::Spec::OS2, File::Spec::Win32, File::Spec::VMS, ExtUtils::MakeMaker
perl v5.18.2 2014-01-06 File::Spec::Functions(3pm)