Swap call by reference confusion Post: 302884686

Sponsored Content

Top Forums Programming Swap call by reference confusion Post 302884686 by Corona688 on Tuesday 21st of January 2014 10:36:24 AM

01-21-2014

Registered User

I've used the two terms interchangably since they do the same thing, in the end.

I suppose you could say a pointer, is a kind of variable which stores addresses.

You are correct that you don't have to dereference a function pointer, but they're special for a reason. Functions are addresses, just like arrays are -- arrays point to data memory, functions point to code memory. The program calls a function by its address. Try this: printf("%p\n", printf); I think C even lets you take the address of main, but C++ doesn't.

You definitely do have to use * for pointers to structures! Either that or the -> operator, which is just a short-form thing which does two things at once. These two statements are equivalent: (*structptr).member vs structptr->member

The same applies to classes, which are just a refinement of structures.

Last edited by Corona688; 01-21-2014 at 11:45 AM..

This User Gave Thanks to Corona688 For This Post:

Corona688

View Public Profile for Corona688

Visit Corona688's homepage!

Find all posts by Corona688

8 More Discussions You Might Find Interesting

1. Solaris

RAM and SWAP confusion

Hi Folks, This is my first post here - so nice to meet u all :-) Recently i was trying to dig a little bit into the memory structure of my machine and due to the lack of concept, cannot figure out a calculation. This is how it goes: 1) My swap slice is at the usual /dev/dsk/c0t1d0s1...

2. Solaris

Swap config - Mirror swap or not?

Hello and thanks in advance. I have a Sun box with raid 1 on the O/S disks using solaris svm. I want to unmirror my swap partition, and add the slice on the second disk as an additional swap device. This would give me twice as much swap space. I have been warned not to do this by some...

3. Infrastructure Monitoring

diffrence between method call and function call in perl

Hello, I have a problem with package and name space. require "/Mehran/DSGateEngineLib/general.pl"; use strict; sub System_Status_Main_Service_Status_Intrusion_Prevention { my %idpstatus; my @result; &General_ReadHash("/var/dsg/idp/settings",\%idpstatus); #print...

4. HP-UX

Swap device file and swap sapce

Hi I have an integrity machine rx7620 and rx8640 running hp-ux 11.31. I'm planning to fine tune the system: - I would like to know when does the memory swap space spill over to the device swap space? - And how much % of memory swap utilization should be specified (swap space device...

5. Programming

call by reference

Ive just started programming in C and am confused with the output of the code void main() { int a=10; int b=20; swapr(a++,b++); printf("%d %d",a,b); } swapr (int *x,int *y) { x+=2; y+=3; } the output of the code is 11,21 which is confusing. first its...

6. UNIX for Dummies Questions & Answers

[Query] Confusion of the Swap when using 'free -m' command

Hi All, I have just installed my first Linux server ( Ubuntu 11.10 ). I am sure I didn't allocate /swap , and double check by 'df -h', yes really no /swap but when I use 'free -m' , returned a "Swap" line as below. total used free shared buffers cached Mem: ...

7. Shell Programming and Scripting

Perl de-reference code reference variable

Guys, May i know how can we de reference the code reference variable.? my $a = sub{$a=shift;$b=shift;print "SUM:",($a+$b),"\n";}; print $a->(4,5); How can we print the whole function ? Please suggest me regarding this. Thanks for your time :) Cheers, Ranga :)

8. Solaris

Explain the output of swap -s and swap -l

Hi Solaris Folks :), I need to calculate the swap usage on solaris server, please let me understand the output of below swap -s and swap -l commands. $swap -s total: 1774912k bytes allocated + 240616k reserved = 2015528k used, 14542512k available $swap -l swapfile dev swaplo...

LEARN ABOUT LINUX

poll_mouse

poll_mouse(3alleg4)						  Allegro manual					       poll_mouse(3alleg4)

NAME

       poll_mouse - Polls the mouse. Allegro game programming library.

SYNOPSIS

       #include <allegro.h>

       int poll_mouse();

DESCRIPTION

       Wherever possible, Allegro will read the mouse input asynchronously (ie.  from inside an interrupt handler), but on some platforms that may
       not be possible, in which case you must call this routine at regular intervals to update the mouse state variables. To help you	test  your
       mouse  polling  code  even  if  you are programming on a platform that doesn't require it, after the first time that you call this function
       Allegro will switch into polling mode, so from that point onwards you will have to call this routine in order to get  any  mouse  input	at
       all, regardless of whether the current driver actually needs to be polled or not.

RETURN VALUE

       Returns zero on success, or a negative number on failure (ie. no mouse driver installed).

SEE ALSO

       mouse_needs_poll(3alleg4),   install_mouse(3alleg4),   mouse_x(3alleg4),   exlights(3alleg4),   exmouse(3alleg4),   exshade(3alleg4),  exs-
       pline(3alleg4), extrans(3alleg4)

Allegro 							   version 4.4.2					       poll_mouse(3alleg4)