How to make build work on IBM i

[chrjorgensen]

Hi.

I found this excellent tool and wanted to port it to IBM i. I'm a newbie in the make tools, but proceeded anyway...

I cloned this repository and followed the build instructions. There was a problem during the linking phase - the linker could not find "libutil_flock".

I could solve this problem by adding " -lutil" to the LDLIBS variable in config.make:

LDLIBS =  -lreadline -lncursesw -liconv -lncursesw -lutil

Now the compile worked and the tig utility was build and running.

I wanted to make the build work directly from the git repository, so I made a new file config.make-OS400 ("OS400" is reported by the uname command):

# Example configuration for IBM i ('uname -s' = OS400)
#
# Use libutil to find flock..

UTIL_LIB = $(shell test -e "/QOpenSys/pkgs/lib/libutil.so.2" && echo true)
HAS_UTIL = $(shell test -e "/QOpenSys/pkgs/lib/libutil.so" && echo true)

ifneq ($(UTIL_LIB),true)
$(error Please install the libutil2 package)
endif

ifneq ($(HAS_UTIL),true)
$(error Please install the libutil-devel package)
endif

TIG_LDLIBS += -lutil

# vim: ft=make:

It was my understanding, that the value of TIG_LDLIBS would be included in the final LDLIBS value for the linker - but it does not work...

My config.make-OS400 is definitely being called - it reports error messages if I remove the libraries tested for - but it does not set the final LDLIBS value.

What am I doing wrong? Please help - when I make it work, I will make a PR so tig can be build on IBM i directly from this repository.

Best regards,
Christian

[krobelus]

That should work.. make sure the file is at contrib/config.make-OS400.

[chrjorgensen]

The file was indeed at contrib/config.make-OS400 - but no the expected output.

Could be me doing something wrong - this is not my strongest field - so I started from scratch:

Clone the repository into new directory
Copy my file into contrib/config.make-OS400
Make new configuration:

make configure
./configure

I still do not see the expexted value in LDLIBS - "-lutil" is still missing in config.make:

LDLIBS =  -lreadline -lncursesw -liconv -lncursesw

The files config.make, config.log and config.status is attached if any help...

config.make
config.log
config.status

[krobelus]

Turns out the problem is that config.make sets LDLIBS.
The Makefile sources that file, and subsequently the line
LDLIBS ?= $(TIG_NCURSES) $(TIG_LDLIBS) has no effect because LDBLIBS is already set.

It worked for me because i didn't run ./configure.
I'm pretty sure it will work for you if you just remove config.make and run make.

I don't see an obvious way to fix the autotools build, but it seems easier to not use it.

[chrjorgensen]

So the build system is apparently broken - no longer using values set by the config.make-$kernel files?

Omitting ./configure does not work on IBM i - IBM i can run AIX (UNIX) binaries due to its PASE environment, but PASE is only a runtime, not a full AIX with libraries for development. ./configure must be run after cloning this repository for the build to find the includes and libraries.

I fixed it by changing my contrib/config.make-OS400 to set its own TIG_variable

TIG_LDLIBS_IBMI = -lutil

and adding the following lines to Makefile

# Use additional libraries on IBM i
LDLIBS += $(TIG_LDLIBS_IBMI)

after calling the two make.config files.

Now I can run ./configure and still have the correct LDLIBS set. And then run the normal make and make install commands.

Any comments on this approach?

Best regards,
Christian

[koutcher]

You're supposed to choose between the original build system and autoconf. For example, config.make-Darwin defines everything you need to build Tig on macOS without having to run configure. If you don't want to add everything to config.make-OS400 (or just can't because of systems variability), then it would be best to teach autoconf to add -lutil when needed rather than adding config.make-OS400:

--- a/configure.ac
+++ b/configure.ac
@@ -36,6 +36,13 @@ AX_LIB_READLINE(6.3)
 
 AM_ICONV
 
+dnl OS-specific
+case $(uname -s 2>/dev/null || echo unknown) in
+OS400)
+    AC_CHECK_LIB(util, main, [LIBS="$LIBS -lutil"], AC_MSG_ERROR([Please install the libutil-devel package]))
+    ;;
+esac
+
 AC_CHECK_PROGS(SED, [gsed], [sed])
 AC_TDD_GCOV
 AC_SUBST(COVERAGE_CFLAGS)

[chrjorgensen]

Ah, thanks for the tip, @koutcher - seems I have a lot to learn about build tools...!
Your solution is much more elegant, and I have incorporated it in configure.ac and will make a PR.

Thank you all for the help!

Best regards,
Christian