473,839 Members | 1,523 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

why is casting malloc a bad thing?

Hello,

I saw on a couple of recent posts people saying that casting the return
value of malloc is bad, like:

d=(double *) malloc(50*sizeo f(double));

why is this bad? I had always thought (perhaps mistakenly) that the
purpose of a void pointer was to cast into a legitimate date type. Is
this wrong? Why, and what is considered to be correct form?

thanks,

Brian Blais

Nov 14 '05
231 23301
On 3 Feb 2004 12:21:35 -0800, ms*****@yahoo.c om (MSG) wrote:
Severian <se******@chlam ydia-is-not-a-flower.com> wrote in message news:<fd******* *************** **********@4ax. com>...
On Sun, 01 Feb 2004 01:29:35 GMT, CBFalconer <cb********@yah oo.com>
wrote:
>Chris, I trust you are making suitable notes. Has anyone got a
>decent Ascii Art version of 'His Masters Voice'. The ineffable
>joy of sitting at the feet of the master!

<snip>
Nice sig!


That was no sig, it was Ascii Art of ERT, the Trollmaster himself,
since I don't have one of 'His Master's Voice'.

--
Sev

Nov 14 '05 #231
On 26 Jan 2004 18:50:46 -0800, qe*@pobox.com (Paul Hsieh) wrote:
<snip>
No, its a language weakness issue. One of the few good things to come
out of the C99 spec is the adoption of C++'s requirement for
prototype, and not assuming the default: int ()(int) . <snip>


C99 does not require prototype forms. It does (changed from C90)
require that functions be *declared* before use; that declaration may
be either prototype or old-style/K&R1; the former is preferable, but
not required. In C90 if you did not declare a function, it was
implicitly int ()() -- unspecified args, not one (of type) int.
- David.Thompson1 at worldnet.att.ne t
Nov 14 '05 #232

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

33
2295
by: hermit_crab67 | last post by:
Can someone explain to a C newbie why this doesn't work as I expect it to work? (expectations clearly outlined in the printf statement in main routine) OS: Linux 2.4.26 GCC: 2.95.4 void modify_pointer(char *); int main(int argc, char *argv) {
35
2719
by: ytrama | last post by:
Hi, I have read in one of old posting that don't cast of pointer which is returned by the malloc. I would like to know the reason. Thanks in advance, YTR
32
2399
by: alex.j.k2 | last post by:
Hello all, I have "PRECISION" defined in the preprocessor code and it could be int, float or double, but I do not know in the code what it is. Now if I want to assign zero to a "PRECISION" variable, which of the following lines are correct:
101
4374
by: Tinkertim | last post by:
Hi, I have often wondered if casting the return value of malloc() (or friends) actually helps anything, recent threads here suggest that it does not .. so I hope to find out. For instance : char *tmp = NULL;
0
9855
marktang
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...
0
9697
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,...
1
10647
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,...
0
10292
tracyyun
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...
1
7828
isladogs
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...
0
7017
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5866
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
4482
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
2
4064
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.

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.