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I would like ./configure to link to a library and some include files. My library is stored in /home/foo/sw/lib/ and my files are stored in /home/foo/sw/include.

./configure --help throws out the following:

Some influential environment variables:

  CC           C compiler command
  CFLAGS       C compiler flags
  LDFLAGS      linker flags, e.g. -L<lib dir> if you have libraries in a 
               nonstandard directory <lib dir>
  LIBS         libraries to pass to the linker, e.g. -l<library>
  CPPFLAGS     (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if 
               you have headers in a nonstandard directory <include dir>
  CPP          C preprocessor

I have tried various combinations:

./configure --prefix=/home/foo/sw -I</home/foo/sw/include> -L</home/foo/sw/lib/>
./configure --prefix=/home/foo/sw -I=/home/foo/sw/include -L=/home/foo/sw/lib/
./configure --prefix=/home/foo/sw -I/home/foo/sw/include -L/home/foo/sw/lib/
etc..

But I can't seem to get the syntax right. If anyone can help me out, that would be greatly appreciated. THANKS!

Braiam
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BlackAdder
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1 Answers1

78

You missed the meaning of

Some influential environment variables:

So you set them as an environment variable; configure determines LDFLAGS and CPPFLAGS by checking config files and the environment. You can set them like this ...

export CPPFLAGS='-I/home/foo/sw/include/'
export LDFLAGS='-L/home/foo/sw/lib/'
./configure

or as a one-liner: 

env CPPFLAGS='-I/home/foo/sw/include/' LDFLAGS='-L/home/foo/sw/lib/' ./configure

Please note that it is possible that you cannot use subdirectories under /home/foo/sw/lib/

f.e. putting your library in /home/foo/sw/lib/bar/ might show you a lib not founderror.

However you can use multiple entries:

LDFLAGS="-L/home/foo/sw/lib/ -L/home/foo/bar/lib/"

Rinzwind
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    Maybe CPPFLAGS='-I/home/foo/sw/include:$CPPFLAGS' just in case something is out there ;) – Braiam Jan 05 '14 at 12:59
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    Hi, Rinzwind. I am confused about the difference between LDFLAGS=-L and LIBS=-l. According to the help, they seems to be the same thing. Is there any difference? – user15964 Mar 01 '17 at 02:21
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    @user15964 -L refers to a directory to search for libraries while -l informs the linker to link against a specific library (to find which it will search the supplied -L directories alongside the default set. – sherrellbc Jun 04 '19 at 16:58
  • Why is there a / after LDFLAGS but not after CPPFLAGS ? Is that a typo, or is it important? – vy32 Jun 07 '19 at 15:14
  • not perse, both work and no. The / at the end signifies it is a directory but it is not needed too include. – Rinzwind Jun 07 '19 at 17:05
  • Wanted to add that, depending upon what's being compiled, the user might have to add their lib directory to the $LD_LIBRARY_PATH environment variable. – chb Nov 14 '19 at 06:30
  • Does not work for cairo – Marat Zakirov Mar 18 '22 at 14:14