On 10/14/20 7:07 PM Hui Peng, Alan Ng wrote:
> Greetings
>
> I am trying to install fltk 1.3.5 on Ubuntu 20.04 without success. I
> have used the following 3 bash shell commands, including results from
> the last command -
>
> alan@alan-Aspire-E1-422:~/reference/fltk-1.3.5$ ./configure
> --enable-debug --disable-gl --enable-shared --enable-threads
> --enable-xdbe --enable-xft
> --includedir=/home/alan/reference/fltk-1.3.5/include
> --bindir=/home/alan/reference/fltk-1.3.5/bin
> --libdir=/home/alan/reference/fltk-1.3.5/lib
> --prefix=/home/alan/reference/fltk-1.3.5
>
> alan@alan-Aspire-E1-422:~/reference/fltk-1.3.5$ make
>
> alan@alan-Aspire-E1-422:~/reference/fltk-1.3.5$ sudo make install
> === installing FL ===
> Installing include files in /home/alan/reference/fltk-1.3.5/include...
> === installing jpeg ===
> Installing ../lib/libfltk_jpeg.a in /home/alan/reference/fltk-1.3.5/lib...
> /usr/bin/install: '../lib/libfltk_jpeg.a' and
> '/home/alan/reference/fltk-1.3.5/lib/libfltk_jpeg.a' are the same file
> make[1]: *** [Makefile:103: install] Error 1
> make: *** [Makefile:33: install] Error 1
>
> config.log is attached for reference.

You are trying to install (with `sudo make install`) to the same
directory you're building FLTK in (error: "'../lib/libfltk_jpeg.a' and
'/home/alan/reference/fltk-1.3.5/lib/libfltk_jpeg.a' are the same file").

There are some issues with your commands:

(1) You do not need to "install" FLTK to use it. If your build (2nd
command: 'make') worked w/o errors you're ready to use FLTK in another
project and you can run the example programs in the test/ folder.

(2) Several of your ./configure command switches are default so you
don't need them, for instance "--enable-threads --enable-xdbe
--enable-xft". You can safely remove these commandline switches.

(3) The following switches are (AFAICT) redundant or even wrong. You
should remove those.

> --includedir=/home/alan/reference/fltk-1.3.5/include
> --bindir=/home/alan/reference/fltk-1.3.5/bin
> --libdir=/home/alan/reference/fltk-1.3.5/lib

(4) You don't need `sudo' if you (really) want to "install" the FLTK
libs to a subdirectory of your home folder (if that's what you did). You
need `sudo' only if you install to a system directory.

(5) If you really want to "install" FLTK (that's fine although not
necessary) and want to use a subdirectory of your home folder I suggest
to use something where you'll maybe install other software as well, e.g.
'/home/alan/dev' or another appropriate directory (not the source
directory of FLTK).

That all said, your configure, build, and install commands might look
like this:

$ ./configure --enable-debug --disable-gl --enable-shared
--prefix=/home/alan/dev

$ make

$ make install

Note that --prefix is used for the install target folder, change this as
required.

One last hint: I'd try to use the defaults when building new software
and amend the commands only when needed. The default values are usually
(and in the FLTK case definitely) a good starting point.

Welcome to the FLTK community, have fun!