Noob Compiling C/C++ code

richard64 · 11-12-2009, 05:26 PM

I'm trying to follow the ALP tutorial (http://www.makelinux.net/alp/). I have just installed Ubuntu 9.04 so the system is pretty much a clean system.

I am trying to compile this code:

Code:

#include <stdio.h> 
#include <tiffio.h> 

int main (int argc, char** argv) 
{
  TIFF* tiff; 
  tiff = TIFFOpen (argv[1], "r"); 
  TIFFClose (tiff); 
  return 0; 
}

Code:

gcc tifftest.c -o tifftest -ltiff

The first problem I get is

Code:

tifftest.c:8:20: error: tiffio.h: No such file or directory

And when I look in /usr/include there is no file tiffio.h. So as a kludge I download the source for libtiff (http://www.libtiff.org/) and I copy the header files to the current directory (change the code appropriately) and try again. Now the code compiles but won't produce the object file:

Code:

/usr/bin/ld: cannot find -ltiff
collect2: ld returned 1 exit status

/uisr/lib has libtiff.so.4 and libtiff.so.4.2.1 so I am at a bit of a loss as to why ld is not finding libtiff.

Does anyone have some suggestions of what I should do now?

1) what do I need to do to install the libtiff header files properly?
2) how do I get gcc to find libtiff?

I am sure these are noob questions, but I haven't need able to find any answers in the searches I have done.

Richard

ammorais · 11-12-2009, 06:10 PM

Code:

sudo apt-get install libtiff4-dev

evo2 · 11-12-2009, 06:22 PM

So it seems you have libtiff4 installed: it provides the libtiff.so.*.

Quote:

1) what do I need to do to install the libtiff header files properly?

libtiff4-dev provides the headers. So please remove the header files you downloaded from www.libtiff.org and then install the libtiff4-dev pacakge.

For libraries this is the standard convention with debian packages: if you want to compile against some lib, you'll need to install the corresponding dev pacakge.

Quote:

2) how do I get gcc to find libtiff?

There does not seem to be anything wrong with your gcc invocation, so I suspect it may just work after you've installed libtiff4-dev.

If you still have problems please post the error, and the output of the following command (will show if libtiff is really installed):

Code:

dpkg -l 'libtiff*'| grep ^ii

Cheers,

Evo2.

knudfl · 11-12-2009, 08:33 PM

Quote:

/usr/bin/ld: cannot find -ltiff

The Library used at link time is lib<name>.so .
( In rare occasions lib<name>.a )
lib<name>.so is a link to "so name" ( libtiff.so.4 )
( sometimes to "real name" ( libtiff.so.4.2.1 ))

'lib<name>.so' is provided by the package lib<name>-dev
together with the headers.
The reason for linking ( ld ) with lib<name>.so is :
You often have more than one version of a library,
and it is your descision, which one to use.

More info about shared libraries :
http://tldp.org/HOWTO/Program-Librar...libraries.html
.....

evo2 · 11-12-2009, 09:44 PM

@knudfl

Thanks for that. I'd always just assumed that the postinst script of libfoo was making the sym links. Guess I'd never experienced the OPs problem since without libfoo-dev the compile would fail, so I would never actaully see the link fail.

Evo2.

richard64 · 11-13-2009, 06:07 AM

Thanks knudfl and evo2 I've been able to get it all working again. The link to shared libraries was also a great help.

Richard