From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: naga raj <gnuuser.raj@gmail.com>
Cc: gcc-help <gcc-help@gcc.gnu.org>
Subject: Re: libstdc++
Date: Fri, 24 Aug 2012 13:40:00 -0000 [thread overview]
Message-ID: <CAH6eHdRpxoPerOwyf0kPhJjCvJDZQqpC7xYCZpu3wj_Va9yjZg@mail.gmail.com> (raw)
In-Reply-To: <CAKuVEhAV-gtkJ4qOHwU4OguKn+Ou_edxA-3iXQNJZz9Az3tL4w@mail.gmail.com>
On 24 August 2012 08:46, naga raj wrote:
> Hi,
>
> I have ported Gcc-4.6.2 to an embedded target. My C++ compiler is
> generating huge code size.
>
> #include <iostream>
> using namespace std;
> int main()
> {
> return 0;
> }
>
> If we execute the above program then all the function in the
> iostream library are included in the elf as a result size of elf is
> increased....
Including <iostream> causes global objects to be constructed, so even
though you're not explicitly using std::cout or std::cin, those
streams are initialized and code is run (before main) just because
<iostream> is included. If you don't need to use it then don't
include it. If you do need to use it then obviously the code size is
larger if you use I/O features than if you don't use them.
That said, libstdc++ isn't really optimised for embedded systems.
Some configure-time options such as building libstdc++ without
exceptions can help reduce code size, if you don't need to use
exceptions.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43852 would also help
avoid dependency on the I/O facilities.
next prev parent reply other threads:[~2012-08-24 9:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-24 8:10 libstdc++ naga raj
2012-08-24 9:33 ` libstdc++ Andrew Haley
2012-08-24 13:40 ` Jonathan Wakely [this message]
2012-08-27 9:27 ` libstdc++ naga raj
-- strict thread matches above, loose matches on Subject: below --
1999-11-04 18:42 libstdc++ Inferno
1999-11-07 5:16 ` libstdc++ J.H.M. Dassen (Ray)
1999-11-30 23:28 ` libstdc++ J.H.M. Dassen (Ray)
1999-11-30 23:28 ` libstdc++ Inferno
1999-10-01 0:00 libstdc++ Inferno
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