[SOLVED] A question about the fmod() function in C...

amwjatyvh · 05-30-2010, 06:39 AM

Can you offer me the code about fmod() in C...
I want to know how this function work, i am very interested in it because i have no idea to implement it, thanks your consideration!

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i want to know... how to write the function... not 'how to use the function'...
can anyone post the source codes of this function here?

brazilnut · 05-30-2010, 06:44 AM

Here's an example:

http://www.codecogs.com/reference/c/math.h/fmod.php

also try:

Code:

$ man fmod

for more info...

ForzaItalia2006 · 05-30-2010, 06:49 AM

Quote:

Originally Posted by amwjatyvh

Can you offer me the code about fmod() in C...
I want to know how this function work, i am very interested in it because i have no idea to implement it, thanks your consideration!

I think the simplest way is to check how the open-source math library (libm) implements this function. Check out the sources of the GNU C library (libm is a part of glibc) and look at

Code:

glibc-x.y/math/w_fmod.c

Andi

amwjatyvh · 05-30-2010, 07:37 AM

Quote:

Originally Posted by brazilnut

Here's an example:

http://www.codecogs.com/reference/c/math.h/fmod.php

also try:

Code:

$ man fmod

for more info...

Oh, may be i haven't explain my question clearly...i am so sorry...

i want to know... how to write the function... not 'how to use the function'... thanks!

ForzaItalia2006 · 05-30-2010, 09:01 AM

Quote:

Originally Posted by amwjatyvh

i want to know... how to write the function... not 'how to use the function'... thanks!

Right! So, why don't you then lookup a reference implementation!? I already posted a link to a reference implementation ... BTW, are you already familiar with the layout of the IEEE floating point specification? I think this is somehow crucial :-) to write such a function ...

Andi

amwjatyvh · 05-30-2010, 09:53 AM

Quote:

Originally Posted by ForzaItalia2006

Right! So, why don't you then lookup a reference implementation!? I already posted a link to a reference implementation ... BTW, are you already familiar with the layout of the IEEE floating point specification? I think this is somehow crucial :-) to write such a function ...

Andi

Oh,my god!Thanks for remind me that link...i feel ashamed...
At first i just glance the site you linked...so i overlook the sentence----"The return value is x - n y, where n is the quotient of x / y, rounded to the first integer towards zero."...i so damn foolish!!!I will be care next time...
To the layout of the IEEE floating point specification...it is my first time to here now and i go to read it right now...
Thanks very much!Please forgive my negligence!

brazilnut · 05-30-2010, 01:27 PM

mmm, syntax is a funny thing...