Where is C99 round function?

Question

First, I post this question to Visual C++ Language but it seems it's OT there, so I repost it here as it relates to VC++ 8.0 libraries

Hi,

It may seem to be extremely trivial quesion, but I completely have no idea why I can not find round function in math.h?

I use VC++ 8.0 so I suppose it brings very up to date C/C++ librareries.

round function was added in C99:

http://www.dinkumware.com/manuals/reader.aspx?b=c/&h=math.html#round

http://www.gnu.org/software/libc/manual/html_mono/libc.html#Rounding%20Functions

I've greped through CRT sources shipped with VC++ 8.0 and there is no such function.

Where can I find it?

Cheers

Answer 1

VC2005 doesn't even have support for C projects that I have seen, nor does it let you add a .c file, you have to do it manually.  I'd be surprised if they supported C99.

 

Answer 2

VC8.0 doesn't fully support the C99 standards as Christian indicated.

Thanks,

Ayman Shoukry

VC++ Team

Answer 3

I'm in shock!
What people pay 800$ for?
I read about "standards conformance" of VC++ 8.0 everwhere so I ask where is that conformance?
Guys, you're working hard to include new and very experimental stuff like C++/CLI but you are not interested in making VC++ conformant to C99, rather old standard?

Please, tell me how widely C++/CLI is used in comparison to C99 features?
C++/CLI even won't be discussed in the nearest ACCU Conference 2006 !

I will never understand Microsoft's way and there is no hope!

Cheers

Answer 4

We are trying to be more conformant to the C++ Standard. We have done some breaking changes for that as well. Nevertheless, I understand your comment. Please go ahead and log it at http://lab.msdn.microsoft.com/productfeedback/default.aspx. This gives us a great way of understanding what the community wants.

BTW, _controlfp could be used in some cases: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclib/html/_crt__control87.2c_._controlfp.asp

Thanks,

Ayman Shoukry

VC++ Team

Answer 5

It's a C++ compiler.  Microsoft is doing amazing things for C++ standards comformance.  The compiler doesn't even offer C projects, nor does it allow you to add a .c file in the IDE, I'd say you're playing with mostly legacy support.  I would imagine the market for a C compiler is about 1-4% of the market for a C++ compiler. 

People pay $800 for a very good C++ compiler, and that is the standards conformance you've been reading about. 

>>Please, tell me how widely C++/CLI is used in comparison to C99 features?

In my world, VB is totally unused, I don't know anyone local to me who uses it.  It sounds like you don't know anyone who uses C++/CLI ( I barely use it myself ).  I know no-one who uses C, let alone C99.  In other words, what you percieve as 'widely used' is a result of the circles you move in.

 

Answer 6

Ayman Shoukry wrote:

We are trying to be more conformant to the C++ Standard. We have done some breaking changes for that as well.

Yes, I know that.

Ayman Shoukry wrote:

Nevertheless, I understand your comment. Please go ahead and log it at http://lab.msdn.microsoft.com/productfeedback/default.aspx. This gives us a great way of understanding what the community wants.

I'm glad you understand my point. I'll give my feedback too.

Ayman Shoukry wrote:

BTW, _controlfp could be used in some cases

Thanks, I'll try it.

Is this true VC++ 8.0 should not be used as a C compiler? I don't understand it. Please, tell me what would you say Charles Petzold's Windows API books readers? AFAIK Petzold's examples are poor C programs. Should they use MinGW?

Simply, I don't get cgraus' point about that VC++ 8.0 is only C++ compilers.

p.s. Certainly, that's clear C++ libraries and programs are based/compatible on C libraries.

Cheers

Answer 7

cgraus wrote:

It's a C++ compiler.

So, now I can try to understand it. As I read in Appendinx C to Standard for Programming Language C++ (working draft):

7 The C++ Standard library provides 209 standard functions from the C library, as shown in Table 102.

And there is no round function in this Table 102. So, now your point seems to be clear.

cgraus wrote:

Microsoft is doing amazing things for C++ standards comformance.

Yes, I know that.

cgraus wrote:

The compiler doesn't even offer C projects, nor does it allow you to add a .c file in the IDE,

You're right, but some time ago it did. How Charles Petzold created his sample projects?

cgraus wrote:

People pay $800 for a very good C++ compiler, and that is the standards conformance you've been reading about.

From this point of view I agree.

Cheers

Answer 8

>> Is this true VC++ 8.0 should not be used as a C compiler? I don't understand it.

Surely the fact that the IDE doesn't actually support you creating .c files, you need to do it by hand, is a sign of how much C was in the mind of the VC++2005 team ?

But, it IS a C compiler.  Just not C99.

>> . Please, tell me what would you say Charles Petzold's Windows API books readers?

LOL - I'd say 'welcome to hell'.  I can't imagine anyone buying VC2005 so they can write Petzold style WndProc programs.

>> Simply, I don't get cgraus' point about that VC++ 8.0 is only C++ compilers.

That's just not my point.  My point is that VC++ is SOLD as a C++ compiler, and I suspect the c compiler support is legacy stuff.  My CORE point is that no-one has ever claimed it would support C99.

>> p.s. Certainly, that's clear C++ libraries and programs are based/compatible on C libraries.

MOST C code will compile in c++.  C99 widens that gap.

http://david.tribble.com/text/cdiffs.htm#C99-fam

Answer 9

cgraus wrote:

>> Is this true VC++ 8.0 should not be used as a C compiler? I don't understand it. Surely the fact that the IDE doesn't actually support you creating .c files, you need to do it by hand, is a sign of how much C was in the mind of the VC++2005 team ? But, it IS a C compiler.  Just not C99.

OK, I have been clarified with this subject now. Thanks.

cgraus wrote:

>> . Please, tell me what would you say Charles Petzold's Windows API books readers? LOL - I'd say 'welcome to hell'.  I can't imagine anyone buying VC2005 so they can write Petzold style WndProc programs.

Yes, I can imagine it :-)

cgraus wrote:

>> Simply, I don't get cgraus' point about that VC++ 8.0 is only C++ compilers. That's just not my point.  My point is that VC++ is SOLD as a C++ compiler, and I suspect the c compiler support is legacy stuff.  My CORE point is that no-one has ever claimed it would support C99.

I understand it.

Cheers

Answer 10

Hello guys, I had the same problem, because I'm starting to use visual C++, but I have a lot of past C code that I want to use in my future C++ projects...it's not a big problem anyway.

 

But I have another question, I've downloaded libc2.5.1 from the web, is it possible to include all of it in my C++ projects?

and if so, how can I do it?

thanks

Francesco