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Top Forums Programming Help on digestion of C header files for a short program. Post 302837669 by Corona688 on Friday 26th of July 2013 11:24:00 AM
Old 07-26-2013
Quote:
Originally Posted by yifangt
Besides the speed, another reason I was trying to go thru them is to modify them for some scenarios of my use---I am always warned "Do not re-invent the wheel!"
There are plenty of reasons to re-invent the wheel. It helps you understand what you're looking at, for one thing.

It is a library, so hopefully you shouldn't need to modify it too much for your own use. The included example code would be a better place to start than the innards...
 

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User::grent(3perl)					 Perl Programmers Reference Guide					User::grent(3perl)

NAME
User::grent - by-name interface to Perl's built-in getgr*() functions SYNOPSIS
use User::grent; $gr = getgrgid(0) or die "No group zero"; if ( $gr->name eq 'wheel' && @{$gr->members} > 1 ) { print "gid zero name wheel, with other members"; } use User::grent qw(:FIELDS); getgrgid(0) or die "No group zero"; if ( $gr_name eq 'wheel' && @gr_members > 1 ) { print "gid zero name wheel, with other members"; } $gr = getgr($whoever); DESCRIPTION
This module's default exports override the core getgrent(), getgruid(), and getgrnam() functions, replacing them with versions that return "User::grent" objects. This object has methods that return the similarly named structure field name from the C's passwd structure from grp.h; namely name, passwd, gid, and members (not mem). The first three return scalars, the last an array reference. You may also import all the structure fields directly into your namespace as regular variables using the :FIELDS import tag. (Note that this still overrides your core functions.) Access these fields as variables named with a preceding "gr_". Thus, "$group_obj->gid()" corresponds to $gr_gid if you import the fields. Array references are available as regular array variables, so "@{ $group_obj->members() }" would be simply @gr_members. The getpw() function is a simple front-end that forwards a numeric argument to getpwuid() and the rest to getpwnam(). To access this functionality without the core overrides, pass the "use" an empty import list, and then access function functions with their full qualified names. On the other hand, the built-ins are still available via the "CORE::" pseudo-package. NOTE
While this class is currently implemented using the Class::Struct module to build a struct-like class, you shouldn't rely upon this. AUTHOR
Tom Christiansen perl v5.14.2 2010-12-30 User::grent(3perl)
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