POSIX module
Hi Perlers, I've seen a lot of tutorial or example code dealing with the POSIX module that does something like this: use POSIX ':sys_wait_h'; What does the ':' mean/do in the above line? --Errin -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
RE: POSIX module
Errin Larsen wrote:
Hi Perlers,
I've seen a lot of tutorial or example code dealing with the POSIX
module that does something like this:
use POSIX ':sys_wait_h';
What does the ':' mean/do in the above line?
It's called a tag and is typically used to import a basket of symbols.
See perldoc Exporter, under the heading Specialised Import Lists
For some reason this isn't documented in my copy of POSIX. But you can see
the symbols exported by running:
$ perl -MPOSIX -le 'print for @{$POSIX::EXPORT_TAGS{sys_wait_h}}'
WEXITSTATUS
WIFEXITED
WIFSIGNALED
WIFSTOPPED
WNOHANG
WSTOPSIG
WTERMSIG
WUNTRACED
(your system may show different values)
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RE: POSIX module
Hi Perlers, I've seen a lot of tutorial or example code dealing with the POSIX module that does something like this: use POSIX ':sys_wait_h'; What does the ':' mean/do in the above line? Besides googling for it, try reading: perldoc perlipc perldoc perldoc -f waitpid perldoc POSIX --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.770 / Virus Database: 517 - Release Date: 9/27/2004 -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: POSIX module
On Wed, 29 Sep 2004 11:32:58 -0400, Jim [EMAIL PROTECTED] wrote: Hi Perlers, I've seen a lot of tutorial or example code dealing with the POSIX module that does something like this: use POSIX ':sys_wait_h'; What does the ':' mean/do in the above line? Besides googling for it, try reading: perldoc perlipc perldoc perldoc -f waitpid perldoc POSIX --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.770 / Virus Database: 517 - Release Date: 9/27/2004 Thank you Bob, and Jim I have read about this. My question is more about the 'use' code then about the POSIX module. It's just a really big module that has a lot of these tags in it, it seems. Here's my problem: When I use the following in my code, it runs and works fine: use POSIX 'setsid'; use POSIX 'errno_h'; use POSIX ':sys_wait_h'; However, when I try to combine those into one line: use POSIX qw/setsid errno_h :sys_wait_h/; Then I get the following error: # ismon.pl :errno_h is not exported by the POSIX module at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 :sys_wait_h is not exported by the POSIX module at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 Can't continue after import errors at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 BEGIN failed--compilation aborted at ./ismon.pl line 3. First of all, I'm not putting a ':' in front of 'errno_h' in my code, but Perl seems to assume it's there ... why? Is there a difference between the two implementations above that I'm not seeing? --Errin -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
RE: POSIX module
Errin Larsen wrote: When I use the following in my code, it runs and works fine: use POSIX 'setsid'; use POSIX 'errno_h'; use POSIX ':sys_wait_h'; However, when I try to combine those into one line: use POSIX qw/setsid errno_h :sys_wait_h/; Then I get the following error: # ismon.pl :errno_h is not exported by the POSIX module at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 :sys_wait_h is not exported by the POSIX module at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 Can't continue after import errors at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 BEGIN failed--compilation aborted at ./ismon.pl line 3. First of all, I'm not putting a ':' in front of 'errno_h' in my code, but Perl seems to assume it's there ... why? POSIX fixes up foo_h as :foo_h for some reason Is there a difference between the two implementations above that I'm not seeing? Exporter only does the special :tag processing if the *first* entry in the import list starts with one of the following characters : ! / So move :sys_wait_h to the front and it will work. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: POSIX module
On Wed, 29 Sep 2004 12:27:03 -0400, Bob Showalter [EMAIL PROTECTED] wrote: Errin Larsen wrote: When I use the following in my code, it runs and works fine: use POSIX 'setsid'; use POSIX 'errno_h'; use POSIX ':sys_wait_h'; However, when I try to combine those into one line: use POSIX qw/setsid errno_h :sys_wait_h/; Then I get the following error: # ismon.pl :errno_h is not exported by the POSIX module at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 :sys_wait_h is not exported by the POSIX module at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 Can't continue after import errors at /usr/perl5/5.6.1/lib/sun4-solaris-64int/POSIX.pm line 19 BEGIN failed--compilation aborted at ./ismon.pl line 3. SNIP Exporter only does the special :tag processing if the *first* entry in the import list starts with one of the following characters : ! / So move :sys_wait_h to the front and it will work. Thanks Bob, that did it. I wonder why that is about Exporter? It seems rather counter-intuitive to me. --Errin -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
