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Re: reducing the libcurl footprint

From: Ganesh Ragavan <>
Date: Tue, 25 Sep 2007 14:30:32 -0700

Thanks for the replies. Following is configuration I am using:

Platform: PowerPC 405
gcc version: 3.3.1
libcurl version: 7.16.4

I included the options that you mentioned in the configure line and used -R
option to remove the .comment section. The size I could get was 146KB after
stripping, though I didn't remove anything from the code. Also I haven't
tried the static linking option yet.

Could you please let me know the architecture that you used for getting the
98 KiB size that you mentioned?
Also could you let me know the other sections like .comment that I could


On 9/24/07, Dan Fandrich <> wrote:
> On Mon, Sep 24, 2007 at 05:18:32PM -0700, Ganesh Ragavan wrote:
> > We are using libcurl for one of our embedded applications in a PowerPC
> > architecture. We are using libcurl for HTTP alone. I am trying to
> reduce the
> > footprint of the library. I used the following configure options:
> >
> > ./configure --target=powerpc-hardhat-linux --host=powerpc-hardhat-linux
> --build
> > =i586-pc-linux-gnu --with-random=/dev/urandom --disable-ftp
> --disable-ldap
> > --disable-dict --disable-telnet --disable-tftp --disable-verbose
> > --disable-debug --disable-manual --disable-sspi --disable-thread
> --disable-ares
> > --disable-cookies --disable-gopher --disable-file --disable-crypto-auth
> > --disable-ipv6 --enable-hidden-symbols --without-ssl --without-libidn
> > --without-zlib --without-libssh2 --without-gnutls --without-nss
> > --without-ca-bundle --without-libidn --without-strerror
> >
> > With the above options and stripping, I can get a library of size 153
> KB. But
> > I cannot afford a size of more than 100 KB. The man page for install
> says that
> > I could get a size as small as 90KB.
> That figure was for the x86 architecture which is more compact than
> PowerPC,
> and it was also for libcurl as of seven releases ago; much has been added
> since then. I just followed the instructions in INSTALL with the CVS
> version
> (post-7.17.0) using gcc 4.2.2 and the figure I get is now 98 KiB.
> Still, you're missing some of the suggestions mentioned in INSTALL. Try
> adding to your configure line:
> CFLAGS='-Os' LDFLAGS='-Wl,-Bsymbolic -Wl,-s'
> to make gcc make size saving optimizations, and have the linker strip
> symbols from your shared library.
> > Also I was looking into the mailing
> > thread at
> >
> > I do not know how to implement the optimizations mentioned in the
> thread.
> > Could someone please explain me with syntax how I could include the
> following
> > optimizations mentioned in the thread?
> >
> > "Since you only want http, the supplied getdate.y is overkill and could
> be
> > greatly dumbed down, saving 10 KB"
> This optimization is already found in the standard curl sources.
> > "By preventing the linking of various unneeded stub files into the
> shared
> > library, you could save couple KB"
> You'll have to manually edit your make files to remove references to
> "empty"
> files like telnet.o and krb4.o so the linker doesn't even try to link
> them.
> You'll probably see the same savings by using an appropriate strip command
> on the linker or objcopy.
> > "If you don't need HTTP digest authentication, you could add some
> #ifdefs in
> > the code and add a --without-digest configure option and safe another 8
> KB"
> This has already been added with the option --disable-crypto-auth
> > "If you don't need verbose error strings, you could add a
> --without-strerror
> > and save another 6 KB"
> This has already been added with the option --disable-verbose
> > Also please let me know of other suggestions that could bring down my
> size.
> Also mentioned in the INSTALL file is to statically link your app,
> avoiding the shared library overhead and any unneeded functions.
> The final suggestion in the INSTALL file is to use the -R option of
> objcopy on the library and remove any unneeded sections (like .comment).
> That means a command like:
> objcopy -R .comment --strip-unneeded lib/
> smaller/
> If you aren't already using gcc ver. 4.x, then doing so will enable
> --enable-hidden-symbols and save a bit more space, and will probably
> give smaller code simply by being on the cutting edge.
> There are more things you could remove from the code if you really wanted
> to get your hands dirty, but the payoff will quickly deteriorate. A
> quick thing to save a few KB would be to compile away failf() in the same
> way as infof().
> >>> Dan
> --
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Received on 2007-09-25