[ug-bosug] datails abt dos.h

[Binu Jose Philip]

"Narendra Kumar.S.S" <ssnkumar at gmail.com> writes:

> Difference is obvious......since g++ uses a different set of libraries.

That is why used a test which used no "obvious libraries", only
the implicit crt1's and such.

Anyway, you are right. C++ is mostly a vastly powerful
pre-processor built over C with libraries to match. If you
don't use those features or those libraries, you will get
only the overhead and not the benefits.

Err.. no, I am not fighting a language war ;-)

cheers
Binu

> -Narendra
>
>
> On 4/7/06, Binu Jose Philip <[[binu.j.philip at sun.com]]> wrote:
>
>           Ananth A <[[writetoananth at gmail.com]]> writes:
>      
>      >>   Yeah C++ compilation is always slower due to overheads. Have you tried
>      >>   adding   extern "C"  for you hello world program to force C linkage and
>      >>   disable the C++ poly-mangled-virtual-inherited-temporarily-constructed-
>      >>   referential overheads ?   I dunno whether this will help though. :-P
>      >
>      > not just compiling but execution speed ( as per wall clock) is also slower.
>      >
>      > most of the overheads were disabled using the cmd line options to g++...
>      
>      As I understand it, the difference is what you link with unless
>      you are compiling c++ code. I have this snippet in x.c:
>      
>      int
>      main()
>      {
>              int i;
>              i = 1;
>              return (0);
>      }
>      
>      $ gcc -c x.c
>      $ g++ -o xCC -c x.c
>      $ gcc -o x_c x.c
>      $ g++ -o x_cc x.c
>      
>      ------- at ---- tmp> ls -l x*
>      -rw-r--r--   1 -------  staff         46 Apr  7 23:04 x.c
>      -rw-r--r--   1 -------  staff        630 Apr  7 23:06 x.o
>      -rw-r--r--   1 -------  staff        630 Apr  7 23:06 xCC.o
>      -rwxr-xr-x   1 -------  staff       6004 Apr  7 23:04 x_c
>      -rwxr-xr-x   1 -------  staff       6108 Apr  7 23:05 x_cc
>      
>      $ diff x.o xCC.o
>      $ diff x_c x_cc
>      Binary files x_c and x_cc differ
>      
>      Needless to say startup is where the speed difference must be.
>      
>      cheers
>      Binu
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>
> --
> Warm Regards,
> S.S.Narendra Kumar
> Visit my blogs at:
> [[http://ssnarendrakumar.blogspot.com/]]
> [[http://blogs.sun.com/roller/page/ssnkumar]]
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