How to tell the compiler where to find libraries.

English Programming/Scripting
#1

Hello,

I am new to programming and building from source code.

How do I tell the compiler during the ./configure process where to find libraries or file dependencies during the build process?

If I only have a “Makefile”, how do I do the same thing as above?

If anyone can help me with this, that would be awesome. If you know of a good website that explains it, that’s great too!

Best,
Aaron

#2

I’m not sure about the configure question.

For compiling from the command line, you have to specify two things for libraries.

  1. Indicate you are using a particular library
    -lmyExample (for library libmyExample)
  2. Indicate what paths should be searched
    -L/home/user/examplePath

For example:
g++ -o test test.cpp -lmyExample -L/home/user/examplePath

Anything you put in the Makefile needs to resolve to something like this.

#3

Ok. So, if in this particular example I need to indicate the path to the TIFF library, and here’s my Makefile:

Varkon libraries

LIBS = IG/lib/IGlib.a
PM/lib/PMlib.a
EX/lib/EXlib.a
DB/lib/DBlib.a
WP/lib/WPlib.a
GE/lib/GElib.a

X11 libraries

XLIBS = -L/usr/X11R6/lib -lX11 -lXext -lXpm

OpenGL libraries. You may have to change this line

to reflect the location of your OpenGL libs.

GLIBS = -lGL -lGLU

The TIFF library

ifeq ($(DV3TIFF),TRUE)
TIFFLIBS = -ltiff
endif

ODBC libraries. You may have to change this line

to reflect the location of your ODBC libs.

ifeq ($(DV3ODBC),TRUE)
SQLLIBS = -L/usr/lib/unixODBC -lmyodbc3
endif

The actual executable, xvarkon.

XVARKON = …/bin/xvarkon

Targets

$(XVARKON): $(LIBS)
cc $(LIBS) $(SQLLIBS) $(XLIBS) $(GLIBS) $(TIFFLIBS) -lm -o $(XVARKON)

Would I change the line TIFFLIBS= -ltiff

or add a new line like:

TIFFLIBS= -L/path/to/my/library

or is it something else entirely?

Thanks.

#4 
TIFFLIBS= -L/path/to/my/library -ltiff

You still need the -l. The -L is not a replacement for -l but tells the linker what other directories to search for libtiff.

#5

Aha! I’ll try that.

Thanks,
Aaron