I have a simple openGL D program that compiles, but I can't get it to link with libglut.a. I've tried a few different command lines:
$ dmd life.d -lglut
$ dmd life.d -L-lglut
$ dmd life.d -L/usr/lib/libglut.a
$ dmd life.d /usr/lib/libglut.a
All of these print the following errors:
life.o:(.data+0x10): undefined reference to `_D1c2gl4glut12__ModuleInfoZ'
life.o:(.data+0x14): undefined reference to `_D1c2gl2gl12__ModuleInfoZ'
life.o: In function `_Dmain':
life.d:(.text._Dmain+0x72): undefined reference to `_D1c2gl4glut8glutInitT1c2gl4glut10pfglutInit'
life.d:(.text._Dmain+0x87): undefined reference to `_D1c2gl4glut19glutInitDisplayModeT1c2gl4glut21pfglutInitDisplayMode'
life.d:(.text._Dmain+0xa1): undefined reference to `_D1c2gl4glut18glutInitWindowSizeT1c2gl4glut20pfglutInitWindowSize'
life.d:(.text._Dmain+0xc2): undefined reference to `_D1c2gl4glut16glutCreateWindowT1c2gl4glut18pfglutCreateWindow'
life.d:(.text._Dmain+0xd7): undefined reference to `_D1c2gl4glut15glutDisplayFuncT1c2gl4glut17pfglutDisplayFunc'
life.d:(.text._Dmain+0xe6): undefined reference to `_D1c2gl4glut12glutMainLoopT1c2gl4glut14pfglutMainLoop'
collect2: ld returned 1 exit status
--- errorlevel 1
Is there a problem with my command lines, or is it something else?
Those look like mangled symbols from D code. You mentioned on your previous question that you were using some kind of compatibility layer – did you make sure to include the files or libraries from that in your build?
Related
I am fairly new to Fortran and this may sound like a silly question. I encounter an error when compiling the Fortran code that is posted as an example in the NLOPT Wiki.
I compile in Ubuntu 18.04 LTS using the following command:
gfortran example-nlopt.f90 -o example-nlopt -I/usr/local/include/
The following error is produced in the terminal:
/tmp/ccbAim6b.o: In function `MAIN__':
example-nlopt.f90:(.text+0x26): undefined reference to `nlo_create_'
example-nlopt.f90:(.text+0x42): undefined reference to `nlo_get_lower_bounds_'
example-nlopt.f90:(.text+0x67): undefined reference to `nlo_set_lower_bounds_'
example-nlopt.f90:(.text+0x8a): undefined reference to `nlo_set_min_objective_'
example-nlopt.f90:(.text+0xca): undefined reference to `nlo_add_inequality_constraint_'
example-nlopt.f90:(.text+0x10e): undefined reference to `nlo_add_inequality_constraint_'
example-nlopt.f90:(.text+0x12d): undefined reference to `nlo_set_xtol_rel_'
example-nlopt.f90:(.text+0x164): undefined reference to `nlo_optimize_'
example-nlopt.f90:(.text+0x305): undefined reference to `nlo_destroy_'
collect2: error: ld returned 1 exit status
Based on what I saw in nlopt's documentation (https://nlopt.readthedocs.io/en/latest/NLopt_Installation/#changing-the-installation-directory) it looks like you just need to specify the library to link against. Maybe try this:
gfortran -I/usr/local/include/ -L/usr/local/lib example-nlopt.f90 -o example-nlopt -lnlopt -lm
This assumes you have the libnlopt.so in /usr/local/lib, if not then point to its location with the -L option.
Overview
I am attempting to convert a C++ project from a Visual Studio solution to a makefile project (using g++), as a first step to supporting multiple platforms with ease. This project requires the Simple DirectMedia Layer 2 (SDL2) and SDL_image libraries. The project previously compiled without errors, and I have since corrected any errors halting the g++ compiler. I am still using Windows x64 and MinGW x64 at this point.
Problem
When linking, g++ throws errors as though there is something wrong with the SDL2 library, claiming that all functions of SDL2 can't be found. However, I know it is finding the libraries, because when I provide an incorrect name or path, I get an explicit error.
Here is my new makefile, apologies if it isn't up to standard:
# Source files
SRC_ENTITIES = Entity_Block.cpp Entity_Controller.cpp Entity_Cursor.cpp Entity_GreenEye.cpp Entity_Harry.cpp
SRC_ENGINE = Game.cpp Sound.cpp SoundManager.cpp Sprite.cpp Texture.cpp TextureManager.cpp Entity.cpp EntityManager.cpp
SRC_ENTRY = main.cpp
# Source and destination
SOURCE = $(SRC_ENTITIES) $(SRC_ENGINE) $(SRC_ENTRY)
DEST = crystal_engine.bin
# Compiler options
OUTPUT = -o $(DEST)
INCLUDES = -I . -I.\include\windows\SDL2-devel-2.0.4-mingw\SDL2-2.0.4\x86_64-w64-mingw32\include\SDL2 -I.\include\windows\SDL2_image-devel-2.0.1-mingw\SDL2_image-2.0.1\x86_64-w64-mingw32\include\SDL2
LIBPATHS = -L.\include\windows\SDL2-devel-2.0.4-mingw\SDL2-2.0.4\x86_64-w64-mingw32\lib -L.\include\windows\SDL2_image-devel-2.0.1-mingw\SDL2_image-2.0.1\x86_64-w64-mingw32\lib
LIBRARIES = -lSDL2 -lSDL2main -lSDL2_image
STANDARD = -std=c++0x
FLAGS = -Wall
default:
echo No task selected
compile:
g++ $(STANDARD) $(INCLUDES) $(FLAGS) $(SOURCE) $(OUTPUT) $(LIBPATHS) $(LIBRARIES)
run:
./$(DEST)
run_win:
$(DEST)
Therefor the command line currently looks like this:
g++ -std=c++0x -I . -I.\include\windows\SDL2-devel-2.0.4-mingw\SDL2-2.0.4\x86_64-w64-mingw32\include\SDL2 -I.\include\windows\SDL2_image-devel-2.0.1-mingw\SDL2_image-2.0.1\x86_64-w64-mingw32\include\SDL2 -Wall Entity_Block.cpp Entity_Controller.cpp Entity_Cursor.cpp Entity_GreenEye.cpp Entity_Harry.cpp Game.cpp Sound.cpp SoundManager.cpp Sprite.cpp Texture.cpp TextureManager.cpp Entity.cpp EntityManager.cpp main.cpp -o crystal_engine.bin -L.\include\windows\SDL2-devel-2.0.4-mingw\SDL2-2.0.4\x86_64-w64-mingw32\lib -L.\include\windows\SDL2_image-devel-2.0.1-mingw\SDL2_image-2.0.1\x86_64-w64-mingw32\lib -lSDL2 -lSDL2main -lSDL2_image
Disregarding warnings (removing -Wall), the output of the compile looks like this:
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x169): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x2b4): undefined reference to `SDL_GetMouseState'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x2c2): undefined reference to `SDL_PollEvent'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x2d0): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x363): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x3ef): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x46c): undefined reference to `SDL_GetTicks'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x4e3): undefined reference to `SDL_RenderClear'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x4fd): undefined reference to `SDL_RenderPresent'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x597): undefined reference to `SDL_ShowCursor'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x5b1): undefined reference to `SDL_Init'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x633): undefined reference to `SDL_CreateRenderer'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x663): undefined reference to `SDL_CreateWindowAndRenderer'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x678): undefined reference to `SDL_SetWindowTitle'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x836): undefined reference to `SDL_SetRenderDrawColor'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x844): undefined reference to `SDL_RenderClear'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x852): undefined reference to `SDL_RenderPresent'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x865): undefined reference to `SDL_SetHint'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x881): undefined reference to `SDL_RenderSetLogicalSize'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x895): undefined reference to `SDL_GL_SetAttribute'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x8a3): undefined reference to `SDL_GetError'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x8d8): undefined reference to `SDL_GL_SetAttribute'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0x8e6): undefined reference to `SDL_GetError'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0xa3d): undefined reference to `SDL_Quit'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0xaba): undefined reference to `SDL_DestroyWindow'
C:\Users\[...]\ccSkHjgE.o:Game.cpp:(.text+0xad1): undefined reference to `SDL_DestroyRenderer'
f:/mingw/mingw-4.8.1/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: C:\Users\[...]\ccSkHjgE.o: bad reloc address 0x1b in section `.text$printf[_printf]'
collect2.exe: error: ld returned 1 exit status
make: *** [compile] Error 1
Troubleshooting
I have tried a number of things from supplying exact paths to libraries to updating SDL from 2.0.3 to 2.0.4. The behavior is the same. There are two include/lib folders in the MinGW devel folder for each architecture, and changing which one I include does not make a difference.
There seems to be a lot of commotion about the order of which arguments are supplied to g++, given the three posts below:
SDL2 Undefined references to functions
Try to change the sequence of the input params:
I've stumbled over this before (on Linux)
https://askubuntu.com/questions/68922/cant-compile-program-that-uses-sdl-after-upgrade-to-11-10-undefined-reference
Ok, solved. Apparently, for some mysterious reason, the order of the gcc options now matters.
http://smf.cataclysmdda.com/index.php?topic=11028.0
It looks like the SDL2_image library is included, but the main SDL2 library is not (the references could be out of order).
Unfortunately, regardless of how I have reordered the arguments, I can't seem to change this result. Unlike with most issues, I haven't even been able to make it any worse! Any and all help is greatly appreciated.
I don't believe this has anything to do with my code, considering a compile without linking -c completes fine, but if it assists with the solution I would be more than happy to post some of it (it is a LOT of code).
Edits
Per request, here is a dump of the full compile with the -v and -Wall options. It is too large for this question so I threw it in a pastebin.
http://pastebin.com/ydET621i
When using the -DDECLSPEC=__declspec(dllimport) option, the output becomes:
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x169): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x2b6): undefined reference to `_imp__SDL_GetMouseState'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x2c6): undefined reference to `_imp__SDL_PollEvent'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x2d6): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x36b): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x3f9): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x478): undefined reference to `_imp__SDL_GetTicks'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x4f1): undefined reference to `_imp__SDL_RenderClear'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x50d): undefined reference to `_imp__SDL_RenderPresent'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x5a9): undefined reference to `_imp__SDL_ShowCursor'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x5c5): undefined reference to `_imp__SDL_Init'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x649): undefined reference to `_imp__SDL_CreateRenderer'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x67b): undefined reference to `_imp__SDL_CreateWindowAndRenderer'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x692): undefined reference to `_imp__SDL_SetWindowTitle'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x852): undefined reference to `_imp__SDL_SetRenderDrawColor'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x862): undefined reference to `_imp__SDL_RenderClear'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x872): undefined reference to `_imp__SDL_RenderPresent'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x887): undefined reference to `_imp__SDL_SetHint'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x8a5): undefined reference to `_imp__SDL_RenderSetLogicalSize'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x8bb): undefined reference to `_imp__SDL_GL_SetAttribute'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x8cb): undefined reference to `_imp__SDL_GetError'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x902): undefined reference to `_imp__SDL_GL_SetAttribute'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0x912): undefined reference to `_imp__SDL_GetError'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0xa6b): undefined reference to `_imp__SDL_Quit'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0xaea): undefined reference to `_imp__SDL_DestroyWindow'
C:\Users\[...]\ccZ61vi9.o:Game.cpp:(.text+0xb03): undefined reference to `_imp__SDL_DestroyRenderer'
f:/mingw/mingw-4.8.1/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: C:\Users\[...]\ccZ61vi9.o: bad reloc address 0x1b in section `.text$printf[_printf]'
collect2.exe: error: ld returned 1 exit status
make: *** [compile] Error 1
Running ar -t libSDL2.a produces the following:
SDL.o
SDL_assert.o
SDL_error.o
SDL_hints.o
SDL_log.o
SDL_atomic.o
SDL_spinlock.o
SDL_audio.o
SDL_audiocvt.o
SDL_audiodev.o
SDL_audiotypecvt.o
SDL_mixer.o
SDL_wave.o
SDL_cpuinfo.o
SDL_dynapi.o
SDL_clipboardevents.o
SDL_dropevents.o
SDL_events.o
SDL_gesture.o
SDL_keyboard.o
SDL_mouse.o
SDL_quit.o
SDL_touch.o
SDL_windowevents.o
SDL_rwops.o
SDL_haptic.o
SDL_gamecontroller.o
SDL_joystick.o
e_atan2.o
e_log.o
e_pow.o
e_rem_pio2.o
e_sqrt.o
k_cos.o
k_rem_pio2.o
k_sin.o
k_tan.o
s_atan.o
s_copysign.o
s_cos.o
s_fabs.o
s_floor.o
s_scalbn.o
s_sin.o
s_tan.o
SDL_power.o
SDL_d3dmath.o
SDL_render.o
SDL_yuv_mmx.o
SDL_yuv_sw.o
SDL_render_d3d.o
SDL_render_d3d11.o
SDL_render_gl.o
SDL_shaders_gl.o
SDL_render_gles.o
SDL_render_gles2.o
SDL_shaders_gles2.o
SDL_render_psp.o
SDL_blendfillrect.o
SDL_blendline.o
SDL_blendpoint.o
SDL_drawline.o
SDL_drawpoint.o
SDL_render_sw.o
SDL_rotate.o
SDL_getenv.o
SDL_iconv.o
SDL_malloc.o
SDL_qsort.o
SDL_stdlib.o
SDL_string.o
SDL_thread.o
SDL_timer.o
SDL_RLEaccel.o
SDL_blit.o
SDL_blit_0.o
SDL_blit_1.o
SDL_blit_A.o
SDL_blit_N.o
SDL_blit_auto.o
SDL_blit_copy.o
SDL_blit_slow.o
SDL_bmp.o
SDL_clipboard.o
SDL_egl.o
SDL_fillrect.o
SDL_pixels.o
SDL_rect.o
SDL_shape.o
SDL_stretch.o
SDL_surface.o
SDL_video.o
SDL_nullevents.o
SDL_nullframebuffer.o
SDL_nullvideo.o
SDL_diskaudio.o
SDL_dummyaudio.o
SDL_windows.o
SDL_xinput.o
SDL_windowsclipboard.o
SDL_windowsevents.o
SDL_windowsframebuffer.o
SDL_windowskeyboard.o
SDL_windowsmessagebox.o
SDL_windowsmodes.o
SDL_windowsmouse.o
SDL_windowsopengl.o
SDL_windowsopengles.o
SDL_windowsshape.o
SDL_windowsvideo.o
SDL_windowswindow.o
SDL_winmm.o
SDL_directsound.o
SDL_xaudio2.o
SDL_dinputjoystick.o
SDL_mmjoystick.o
SDL_windowsjoystick.o
SDL_xinputjoystick.o
SDL_dinputhaptic.o
SDL_windowshaptic.o
SDL_xinputhaptic.o
SDL_syspower.o
SDL_sysfilesystem.o
SDL_sysmutex.o
SDL_syssem.o
SDL_systhread.o
SDL_systls.o
SDL_syscond.o
SDL_systimer.o
SDL_sysloadso.o
Thanks to suggestions from #J.JHakala and #user657267 I have reached the conclusion that my installation of MinGW is actually 32 bit! Given that I was using the 64 bit libraries, they would read in like any other library, but the functions within them were not recognized.
For anyone else having this problem, you can download the 64 bit version of MinGW or alternatively just switch which libraries you are importing.
x86: i686-w64-mingw32
x64: x86_64-w64-mingw32
I try to compile a source file which include the <regex.h> with i586-mingw32msvc-gcc:
$ i586-mingw32msvc-gcc parser.c -Ilibregex/include -o parser.o
And I get this:
/tmp/ccPpDhjW.o:parser.c:(.text+0xfd): undefined reference to `__imp__regcomp'
/tmp/ccPpDhjW.o:parser.c:(.text+0x144): undefined reference to `__imp__regexec'
/tmp/ccPpDhjW.o:parser.c:(.text+0x158): undefined reference to `__imp__regfree'
/tmp/ccPpDhjW.o:parser.c:(.text+0x18f): undefined reference to `__imp__regcomp'
/tmp/ccPpDhjW.o:parser.c:(.text+0x1b8): undefined reference to `__imp__regerror'
/tmp/ccPpDhjW.o:parser.c:(.text+0x1fc): undefined reference to `__imp__regexec'
/usr/lib/gcc/i586-mingw32msvc/4.2.1-sjlj/../../../../i586-mingw32msvc/lib/libmingw32.a(main.o):(.text+0x85): undefined reference to `_WinMain#16'
collect2: ld returned 1 exit status
My folder libregex/include contains the regex.h.
Has anyone tried to compile a source containing <regex.h> with mingw in cross compilation?
Try adding #define PCRE_STATIC before including pcreposix.h.
add -lregex
which works fine with msys2 w64-x86_64
I have a simple socket program that I'm trying to compile using g++ running in mingw (both the latest versions) on a Win8 system. I'm getting the common linker errors
undefined reference to `__imp_socket'
undefined reference to `__imp_gethostbyname'
I've tried adding -lws2_32 with no luck; i.e. it still can't find the references. Can someone suggest something else I might be missing?
Here's the full output:
G:\source\kak>g++ -o ./test_client -lws2_32 test_client.C
C:\Users\kenkahn\AppData\Local\Temp\ccDZTr9b.o:test_client.C:(.text+0x4f): undefined reference to `__imp_inet_addr'
C:\Users\kenkahn\AppData\Local\Temp\ccDZTr9b.o:test_client.C:(.text+0x6b): undefined reference to `__imp_socket'
C:\Users\kenkahn\AppData\Local\Temp\ccDZTr9b.o:test_client.C:(.text+0x8b): undefined reference to `__imp_connect'
d:/program files/mingw/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/4.8.1/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\Users\kenkahn\AppData\Local\Temp\ccDZTr9b.o: bad reloc address 0xc in section `.xdata'
collect2.exe: error: ld returned 1 exit status
Try putting the -lws2_32 after the test_client.C parameter. The linker of gcc (ld) is touchy about the order of linkable things, this is probably why it doesn't find your imported functions at link time.
Ok, newb question here.
I'm trying to compile simple_xy_wr.f90 -- a netCDF example program -- using gfortran on Ubuntu, and I must be doing something pretty silly; I don't have much experince compiling Fortran.
First, I've got the libnetcdf-dev package installed, which includes files like
/usr/lib/libnetcdf.a
/usr/lib/libnetcdff.a
/usr/include/netcdf.mod
So, I've tried to compile the code with (various command like)
f95 -o xy -I/usr/include/ -L/usr/lib/ -lnetcdff -lnetcdf simple_xy_wr.f90
and I get the following output
/tmp/ccE6g7sr.o: In function `check.1847':
simple_xy_wr.f90:(.text+0x72): undefined reference to `__netcdf_MOD_nf90_strerror'
/tmp/ccE6g7sr.o: In function `MAIN__':
simple_xy_wr.f90:(.text+0x284): undefined reference to `__netcdf_MOD_nf90_create'
simple_xy_wr.f90:(.text+0x2b6): undefined reference to `__netcdf_MOD_nf90_def_dim'
simple_xy_wr.f90:(.text+0x2e8): undefined reference to `__netcdf_MOD_nf90_def_dim'
simple_xy_wr.f90:(.text+0x432): undefined reference to `__netcdf_MOD_nf90_def_var_manydims'
simple_xy_wr.f90:(.text+0x468): undefined reference to `__netcdf_MOD_nf90_enddef'
simple_xy_wr.f90:(.text+0x4aa): undefined reference to `__netcdf_MOD_nf90_put_var_2d_fourbyteint'
simple_xy_wr.f90:(.text+0x4cb): undefined reference to `__netcdf_MOD_nf90_close'
collect2: error: ld returned 1 exit status
I think that I'm including the right libraries. E.g. it seems that __netcdf_MOD_nf90_strerror should be there:
$ nm /usr/lib/libnetcdff.a | grep __netcdf_MOD_nf90_strerror
000000000004a100 T __netcdf_MOD_nf90_strerror
What am I doing wrong?
(FWIW, a few relevant references I've looked at are below.
undefined reference using netcdf library
Compiling problems with gfortran and NETCDF
Compiling and Running Fortran Programs - a basic guide
)
Ordering of object files and archives on the linker command line is very important on Unix systems since the default linker behaviour is to search for symbol definitions only in archives that follow the object file or archive, where an unresolved reference was found, referred to single pass linking.
This means that if your code references __netcdf_MOD_nf90_strerror, then the archive that contains the definition of this symbol (libnetcdff.a) must appear after the list of object files from your program. libnetcdff.a itself references symbols from the C library libnetcdf.a, hence it must be linked after libnetcdff.a. So the correct link order is:
/tmp/ccE6g7sr.o libnetcdff.a libnetcdf.a
where /tmp/ccE6g7sr.o is the temporary object file that the assembler produces from the compiled source file. The correct command line to compile your code is then:
f95 -o xy -I/usr/include/ simple_xy_wr.f90 -lnetcdff -lnetcdf
In this case the linker is not called directly, rather the compiler does it. GCC compilers pass all link-related things in the same order to an intermediate utility called collect2 which then calls the actual linker ld.
Note that if shared object versions of the netCDF library archives are also present (i.e. there are libnetcdff.so and libnetcdf.so), then the linker would prefer them to the static archives (unless static linking is enabled with the -static option) and the final link phase would be handled to the run-time link editor (RTLD) (/lib64/ld-linux-x86-64.so.2 on Ubuntu). In this case the same command line as in your question would actually succeed without link errors, despite the fact that both libraries are positioned before the code that references them, as the missing symbol references would be resolved by the RTLD while it is loading the executable file.
In Ubuntu 12.10, the order of the libraries is the trick (as Hristo suggested):
angelv#palas:~$ gfortran -o xy -I/usr/include/ -L/usr/lib/ -lnetcdf -lnetcdff simple_xy_wr.f90
/tmp/ccj95anF.o: In function `check.1847':
simple_xy_wr.f90:(.text+0x72): undefined reference to `__netcdf_MOD_nf90_strerror'
/tmp/ccj95anF.o: In function `MAIN__':
simple_xy_wr.f90:(.text+0x284): undefined reference to `__netcdf_MOD_nf90_create'
simple_xy_wr.f90:(.text+0x2b6): undefined reference to `__netcdf_MOD_nf90_def_dim'
simple_xy_wr.f90:(.text+0x2e8): undefined reference to `__netcdf_MOD_nf90_def_dim'
simple_xy_wr.f90:(.text+0x432): undefined reference to `__netcdf_MOD_nf90_def_var_manydims'
simple_xy_wr.f90:(.text+0x468): undefined reference to `__netcdf_MOD_nf90_enddef'
simple_xy_wr.f90:(.text+0x4aa): undefined reference to `__netcdf_MOD_nf90_put_var_2d_fourbyteint'
simple_xy_wr.f90:(.text+0x4cb): undefined reference to `__netcdf_MOD_nf90_close'
collect2: error: ld returned 1 exit status
angelv#palas:~$ gfortran -o xy -I/usr/include/ simple_xy_wr.f90 -L/usr/lib/ -lnetcdf -lnetcdff
angelv#palas:~$ ./xy
0 12 24 36
*** SUCCESS writing example file simple_xy.nc!