[ug-bosug] datails abt dos.h

[Binu Jose Philip]

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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