473,327 Members | 1,930 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,327 software developers and data experts.

what does this mean

std::map <int, struct net_interface> *ifaces = (std::map <int, struct net_interface> *) arg;

I whant to know what type of data is arg after this expression is included in the program, the rest of the variables are known to me.
thx
Apr 28 '07 #1
4 1081
std::map <int, struct net_interface> *ifaces = (std::map <int, struct net_interface> *) arg;

I whant to know what type of data is arg after this expression is included in the program, the rest of the variables are known to me.
thx
In the first part, you are declaring a pointer to a map object...
Thus, arg will be an existing pointer to another map object.
Apr 28 '07 #2
In the first part, you are declaring a pointer to a map object...
Thus, arg will be an existing pointer to another map object.
I think that arg is type casted to a pointer to an map object. Let me know what do you think about this possibility
Apr 28 '07 #3
weaknessforcats
9,208 Expert Mod 8TB
Actually, I'm more interested in why all this type casting.

Generally in C++ you cast for two reasons:
1) you are calling legacy C code that uses void*
2) your C++ design is weak. That is, if you have to tell a C++ compiler what the type is, you have a design problem.
Apr 28 '07 #4
Actually, I'm more interested in why all this type casting.

Generally in C++ you cast for two reasons:
1) you are calling legacy C code that uses void*
2) your C++ design is weak. That is, if you have to tell a C++ compiler what the type is, you have a design problem.

Here is the first case situation, i am using code from libpcap library. Thx for the observation anyway.
Apr 29 '07 #5

Sign in to post your reply or Sign up for a free account.

Similar topics

125
by: Sarah Tanembaum | last post by:
Beside its an opensource and supported by community, what's the fundamental differences between PostgreSQL and those high-price commercial database (and some are bloated such as Oracle) from...
3
by: Jukka K. Korpela | last post by:
I have noticed that the meaning of visibility: collapse has been discussed on different forums, but with no consensus on what it really means. Besides, implementations differ. The specification...
86
by: Michael Kalina | last post by:
Because when I asked for comments on my site-design (Remember? My site, your opinion!) some of you told me never to change anything on font-sizes! What do you guys think of that:...
44
by: lester | last post by:
a pre-beginner's question: what is the pros and cons of .net, compared to ++ I am wondering what can I get if I continue to learn C# after I have learned C --> C++ --> C# ?? I think there...
2
by: Steve Richter | last post by:
What does the "." mean in the following sql script stmts? use GO if exists (select * from dbo.sysobjects where id = object_id(N'.') and OBJECTPROPERTY(id,N'IsUserTable') = 1) drop table ....
121
by: typingcat | last post by:
First of all, I'm an Asian and I need to input Japanese, Korean and so on. I've tried many PHP IDEs today, but almost non of them supported Unicode (UTF-8) file. I've found that the only Unicode...
51
by: jacob navia | last post by:
I would like to add at the beginning of the C tutorial I am writing a short blurb about what "types" are. I came up with the following text. Please can you comment? Did I miss something? Is...
1
by: Frank Rizzo | last post by:
Some of the classes in the framework are marked as thread-safe in the documentation. In particular the docs say the following: "Any public static (*Shared* in Visual Basic) members of this type...
13
by: Jason Huang | last post by:
Hi, Would someone explain the following coding more detail for me? What's the ( ) for? CurrentText = (TextBox)e.Item.Cells.Controls; Thanks. Jason
9
by: JoeC | last post by:
m_iWidth = (int)pBitmapInfo->bmiHeader.biWidth; m_iHeight = (int)pBitmapInfo->bmiHeader.biHeight; What does this mean? I have seen v=&var->member.thing; but what does it mean when you...
0
by: DolphinDB | last post by:
Tired of spending countless mintues downsampling your data? Look no further! In this article, you’ll learn how to efficiently downsample 6.48 billion high-frequency records to 61 million...
0
by: ryjfgjl | last post by:
ExcelToDatabase: batch import excel into database automatically...
0
by: jfyes | last post by:
As a hardware engineer, after seeing that CEIWEI recently released a new tool for Modbus RTU Over TCP/UDP filtering and monitoring, I actively went to its official website to take a look. It turned...
1
by: CloudSolutions | last post by:
Introduction: For many beginners and individual users, requiring a credit card and email registration may pose a barrier when starting to use cloud servers. However, some cloud server providers now...
1
by: Defcon1945 | last post by:
I'm trying to learn Python using Pycharm but import shutil doesn't work
1
by: Shællîpôpï 09 | last post by:
If u are using a keypad phone, how do u turn on JavaScript, to access features like WhatsApp, Facebook, Instagram....
0
by: af34tf | last post by:
Hi Guys, I have a domain whose name is BytesLimited.com, and I want to sell it. Does anyone know about platforms that allow me to list my domain in auction for free. Thank you
0
by: Faith0G | last post by:
I am starting a new it consulting business and it's been a while since I setup a new website. Is wordpress still the best web based software for hosting a 5 page website? The webpages will be...
0
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 3 Apr 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome former...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.