Re: [udunits] [UDUNITS #KIA-819973]: Build and run problem on ubuntu 13.10 32bits

• To: support-udunits@xxxxxxxxxxxxxxxx
• Subject: Re: [udunits] [UDUNITS #KIA-819973]: Build and run problem on ubuntu 13.10 32bits
• From: chris <chgans@xxxxxxxxxxxxxx>
• Date: Wed, 16 Apr 2014 10:42:58 +1200

On 16/04/14 07:32, Unidata UDUNITS Support wrote:

Chris,

What is the value of the MATH_LIBRARY variable in the file "CMakeCache.txt", 
which should be in the top-level build-directory?

$ grep MATH_LIB CMakeCache.txt
MATH_LIBRARY:FILEPATH=/usr/lib/i386-linux-gnu/libm.so

Chris

My point is: The latest udunits doesn't build on ubuntu:

$ rm -Rf build && mkdir build && cd build
$ cmake ..
$ make
Scanning dependencies of target udunits2_doc
[  5%] Built target udunits2_doc
Scanning dependencies of target libudunits2
[ 10%] Building C object lib/CMakeFiles/libudunits2.dir/converter.c.o
[ 15%] Building C object lib/CMakeFiles/libudunits2.dir/error.c.o
[ 21%] Building C object lib/CMakeFiles/libudunits2.dir/formatter.c.o
[ 26%] Building C object lib/CMakeFiles/libudunits2.dir/idToUnitMap.c.o
[ 31%] Building C object lib/CMakeFiles/libudunits2.dir/parser.c.o
[ 36%] Building C object lib/CMakeFiles/libudunits2.dir/prefix.c.o
[ 42%] Building C object lib/CMakeFiles/libudunits2.dir/status.c.o
[ 47%] Building C object lib/CMakeFiles/libudunits2.dir/systemMap.c.o
[ 52%] Building C object lib/CMakeFiles/libudunits2.dir/unitAndId.c.o
[ 57%] Building C object lib/CMakeFiles/libudunits2.dir/unitcore.c.o
[ 63%] Building C object lib/CMakeFiles/libudunits2.dir/unitToIdMap.c.o
[ 68%] Building C object lib/CMakeFiles/libudunits2.dir/ut_free_system.c.o
[ 73%] Building C object lib/CMakeFiles/libudunits2.dir/xml.c.o
Linking C shared library libudunits2.so
[ 84%] Built target libudunits2
Scanning dependencies of target udunits2lib_doc
[ 89%] Built target udunits2lib_doc
Scanning dependencies of target udunits2
[ 94%] Building C object prog/CMakeFiles/udunits2.dir/udunits2.c.o
Linking C executable udunits2
../lib/libudunits2.so: undefined reference to `fmod'
../lib/libudunits2.so: undefined reference to `exp'
../lib/libudunits2.so: undefined reference to `log'
../lib/libudunits2.so: undefined reference to `pow'
../lib/libudunits2.so: undefined reference to `log10'
../lib/libudunits2.so: undefined reference to `floor'
collect2: error: ld returned 1 exit status
make[2]: *** [prog/udunits2] Error 1
make[1]: *** [prog/CMakeFiles/udunits2.dir/all] Error 2
make: *** [all] Error 2

The only way to fix it is to tell gcc that libudunits depends on libm
while generating the .so:

Original command:
/usr/bin/cc  -fPIC    -shared -Wl,-soname,libudunits2.so -o
libudunits2.so [...] -lexpat
Fixed command:
/usr/bin/cc  -fPIC    -shared -Wl,-soname,libudunits2.so -o
libudunits2.so [...] -lexpat -lm

After the fix:
$ make
[  5%] Built target udunits2_doc
[ 84%] Built target libudunits2
[ 89%] Built target udunits2lib_doc
Linking C executable udunits2
[ 94%] Built target udunits2
Scanning dependencies of target udunits2prog_doc
[100%] Built target udunits2prog_doc

The sense of the "res == 0" test in the above is inverted: the
function returns false (i.e., 0) if and only if numeric values are not
convertible between the two units.

My bad! Actually the documentation is clear enough on that point.

You should use ut_free(ut_unit*) and ut_free_system(ut_unit_system*)
in the above instead of free(). The documentation needs to be improved
in the area. I'll get on that.

My bad again, I think the documentation is clear enough.

The above warnings are expected for the reasons given. You can disable them.

Good, I think i will eventually customise my unit definitions.

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: KIA-819973
Department: Support UDUNITS
Priority: Normal
Status: Closed

• References:
  • [udunits] [UDUNITS #KIA-819973]: Build and run problem on ubuntu 13.10 32bits
    • From: Unidata UDUNITS Support