Well, you should specify that you want to print scalar, you're missing the " $ ", the following example works OK :
If you want to capture system command's output, you should not use system(), as it only returns the status of wait(). Use backticks instead as shown above.
What does the system call "dup" do?
What is the difference between dup and dup2
I have a fair idea of what it does but I am confused when its coming down to the exact details...
Please help me!:confused: (2 Replies)
open, creat, read, write, lseek and close
Are they all primitive?
:confused:
*Another Question: is there a different between a system call, and an i/o system call? (2 Replies)
Hi,
I'm new to UNIX system calls. Can someone share your knowledge as to how exactly system calls should be executed?
Can they be typed like commands such as mkdir on the terminal itself? Also, are there any websites which will show me an example of the output to expect when a system call like... (1 Reply)
Hello,
how would i be able to call ps in C programming?
thanks,
---------- Post updated at 01:39 AM ---------- Previous update was at 01:31 AM ----------
here's the complete system call, ps -o pid -p %d, getpit() (2 Replies)
All,
Kindly let me know command which is used to trace the system calls on HP - UX server when an executable is run.
On Solaris we have TRUSS which does the need. On HP UX we have TUSC command which is a third party software. Currently this is not installed on my HP Server. If there... (3 Replies)
Perl::Critic::Policy::ValuesAndExpressions::ProhibitCommUseraContriPerl::Critic::Policy::ValuesAndExpressions::ProhibitCommaSeparatedStatements(3)NAME
Perl::Critic::Policy::ValuesAndExpressions::ProhibitCommaSeparatedStatements - Don't use the comma operator as a statement separator.
AFFILIATION
This Policy is part of the core Perl::Critic distribution.
DESCRIPTION
Perl's comma statement separator has really low precedence, which leads to code that looks like it's using the comma list element separator
not actually doing so. Conway suggests that the statement separator not be used in order to prevent this situation.
The confusion that the statement separator causes is primarily due to the assignment operators having higher precedence.
For example, trying to combine two arrays into another like this won't work:
@x = @y, @z;
because it is equivalent to
@x = @y;
@z;
Conversely, there are the built-in functions, like "print", that normally force the rest of the statement into list context, but don't when
called like a subroutine.
This is not likely to produce what is intended:
print join q{, }, 2, 3, 5, 7, ": the single-digit primes.
";
The obvious fix is to add parentheses. Placing them like
print join( q{, }, 2, 3, 5, 7 ), ": the single-digit primes.
";
will work, but
print ( join q{, }, 2, 3, 5, 7 ), ": the single-digit primes.
";
will not, because it is equivalent to
print( join q{, }, 2, 3, 5, 7 );
": the single-digit primes.
";
CONFIGURATION
This policy can be configured to allow the last statement in a "map" or "grep" block to be comma separated. This is done via the
"allow_last_statement_to_be_comma_separated_in_map_and_grep" option like so:
[ValuesAndExpressions::ProhibitCommaSeparatedStatements]
allow_last_statement_to_be_comma_separated_in_map_and_grep = 1
With this option off (the default), the following code violates this policy.
%hash = map {$_, 1} @list;
With this option on, this statement is allowed. Even if this option is off, using a fat comma "=>" works, but that forces stringification
on the first value, which may not be what you want.
BUGS
Needs to check for "scalar( something, something )".
AUTHOR
Elliot Shank "<perl@galumph.com>"
COPYRIGHT
Copyright (c) 2007-2011 Elliot Shank.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license
can be found in the LICENSE file included with this module.
perl v5.16.3Perl::Critic::Policy::ValuesAndExpressions::ProhibitCommaSeparatedStatements(3)