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by: Zhiqiang Ye |
last post by:
Hi, All
I am reading FAQ of this group. I have a question about this:
http://www.eskimo.com/~scs/C-faq/q7.31.html
It says:
"
p = malloc(m * n);
memset(p, 0, m * n);
The zero fill is all-bits-zero, and does not therefore guarantee useful null
pointer values (see section 5 of this list) or floating-point zero values.
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by: junky_fellow |
last post by:
Can 0x0 be a valid virtual address in the address space
of an application ?
If it is valid, then the location pointed by a NULL pointer
is also valid and application should not receive "SIGSEGV"
( i am talking of unix machine ) while trying to read that
location.
Then how can i distinguish between a NULL pointer and an invalid
location ?
Is this essential that NULL pointer should not point to any of
the location in the virtual address...
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by: pm940 |
last post by:
Hello.
I've been reading some past discussions on the NULL vs. zero.
References are always made to systems or machienes that use values
other than zero to represent the NULL pointer.
Although not a practice I follow, there are no doubt millions of lines
of open source libraries and applications that do things like:
p = malloc(...);
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by: Raed Sawalha |
last post by:
I'm capturing the screen using the following code , but the problem i have
that after 43 calls of the functions the NULL reference object is returned ,
SIZE size;
//Here we get the handle to the desktop device context.
IntPtr hDC =
PlatformInvokeUSER32.GetDC(PlatformInvokeUSER32.GetDesktopWindow());
//Here we make a compatible device context in memory for screen device
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by: Asha |
last post by:
greetings, i have some questions below, what are the differences between
private string _strVal = string.Empty; and _strVal = null;
does the string.Empty; allocate memory for it? how about _strVal = ""
thanks for enlightening me on this.
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by: Randall Parker |
last post by:
I am designing a database schema. It happens to be in MySQL but I'm trying to keep it
portable to other databases should the project grow.
Anyway, suppose you have VARCHAR fields and will be using ASP.Net and ADO.Net. In
your experience does it make more sense to allow NULL values for VARCHAR fields or
will they behave well and get set to zero length strings when a user doesn't fill in
a text field?
I'm wondering if I should do:
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by: z.ghulam |
last post by:
Hi,
I have a line graph used to tally up the number of orders each engineer
does in a week. This works well apart from 2 things:
1) If an engineer is off for a week or completes 0 orders, then there
is no record of a 0 in the database and so there is a break in the line
graph. Whjat I would like is the line graph to show a value of 0 for
these periods. Is there any way to get Access to create a default zero
value in the graph if no...
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by: khan |
last post by:
Hi,
I read that pointer representation can non-zero bit pattern, machine
specific.Compiler when comes accross value '0' in pointer context,
converts it to machine specific null pointer bit-pattern.
My question is if a program refers to that specific value which is
used by the machine to refer to null pointer, how compiler treats
that?.
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by: ADezii |
last post by:
Null as it relates to database development is one of life's little mysteries and a topic of total confusion for novices who venture out into the database world. A Null Value is not zero (0), a zero (0) length string, an empty Field, or no value at all - so exactly what is Null? The purpose of this Topic is hopefully to explain what a Null Value is, discuss some peculiarities about Nulls, show how we can detect them, and finally, how to convert...
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by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
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by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
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by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
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by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
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by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own....
Now, this would greatly impact the work of software developers. The idea...
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by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 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 a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms.
Adolph will...
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by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
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by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
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