• Jeremy DeHaan (10/10) Mar 13 2013 Hey guys!
• Timon Gehr (3/13) Mar 13 2013 There is no additional overhead (though the D compiler will not be able
• Artur Skawina (17/29) Mar 14 2013 Like Timon said - there's is zero overhead.
• John Colvin (4/27) Mar 14 2013 A decent link-time optimiser will be able to do the inlining
• Andrea Fontana (2/4) Mar 14 2013 Are you going to publish this binding? Which library?

"Jeremy DeHaan" <dehaan.jeremiah gmail.com> writes:

Hey guys!

I am working on a binding for D, and am almost finished! I 
started to think of some things I might like to work on to 
improve the binding after I get everything working, and one of 
the things I thought of was rewriting certain parts to use only D 
code instead of making calls to the C functions. Is there any 
kind of performance overhead in using C libraries to interact 
with your D program? If it isn't going to offer much performance 
gain then I probably don't need to bother writing extra code.

Thanks as usual!

Timon Gehr <timon.gehr gmx.ch> writes:

On 03/14/2013 01:48 AM, Jeremy DeHaan wrote:
 Hey guys!

 I am working on a binding for D, and am almost finished! I started to
 think of some things I might like to work on to improve the binding
 after I get everything working, and one of the things I thought of was
 rewriting certain parts to use only D code instead of making calls to
 the C functions. Is there any kind of performance overhead in using C
 libraries to interact with your D program? If it isn't going to offer
 much performance gain then I probably don't need to bother writing extra
 code.

 Thanks as usual!

There is no additional overhead (though the D compiler will not be able 
to inline C functions, whereas an identical D function may be inlined.)

Artur Skawina <art.08.09 gmail.com> writes:

On 03/14/13 01:52, Timon Gehr wrote:
 On 03/14/2013 01:48 AM, Jeremy DeHaan wrote:
 I am working on a binding for D, and am almost finished! I started to
 think of some things I might like to work on to improve the binding
 after I get everything working, and one of the things I thought of was
 rewriting certain parts to use only D code instead of making calls to
 the C functions. Is there any kind of performance overhead in using C
 libraries to interact with your D program? If it isn't going to offer
 much performance gain then I probably don't need to bother writing extra
 code.

 
 There is no additional overhead (though the D compiler will not be able to
inline C functions, whereas an identical D function may be inlined.)

Like Timon said - there's is zero overhead.
Even the inlining limitation only applies to /some/ compilers. [1]


xlanginline1.d:
   extern extern(C) int c();
   int main() { return 2*c(); }

xlanginline2.c:
   int c() { return 21; };

compiled with GDC + -flto:

08049820 <_Dmain>:
 8049820:       55                      push   %ebp
 8049821:       b8 2a 00 00 00          mov    $0x2a,%eax
 8049826:       89 e5                   mov    %esp,%ebp
 8049828:       5d                      pop    %ebp
 8049829:       c3                      ret    

artur

[1] and versions, unfortunately.

"John Colvin" <john.loughran.colvin gmail.com> writes:

On Thursday, 14 March 2013 at 00:52:41 UTC, Timon Gehr wrote:
 On 03/14/2013 01:48 AM, Jeremy DeHaan wrote:
 Hey guys!

 I am working on a binding for D, and am almost finished! I 
 started to
 think of some things I might like to work on to improve the 
 binding
 after I get everything working, and one of the things I 
 thought of was
 rewriting certain parts to use only D code instead of making 
 calls to
 the C functions. Is there any kind of performance overhead in 
 using C
 libraries to interact with your D program? If it isn't going 
 to offer
 much performance gain then I probably don't need to bother 
 writing extra
 code.

 Thanks as usual!

 There is no additional overhead (though the D compiler will not 
 be able to inline C functions, whereas an identical D function 
 may be inlined.)

A decent link-time optimiser will be able to do the inlining 
where appropriate. gdc can be compiled with lto enabled, as Artur 
shows in his reply.

"Andrea Fontana" <nospam example.com> writes:

On Thursday, 14 March 2013 at 00:48:53 UTC, Jeremy DeHaan wrote:
 Hey guys!

 I am working on a binding for D, and am almost finished!

Are you going to publish this binding? Which library?