I have two object files, one with a symbol that is undefined (from standard input):
bin/src/ghdl_grt/ghwlib.c.o: U sched_getstreams
...and one with the same symbol that is defined:
bin/src/nuttx/nuttx/nuttx.o:0000000000004f0c T sched_getstreams
When I try to link them together, the symbol is for some reason still undefined:
$ ld bin/src/ghdl_grt/ghwlib.c.o bin/src/nuttx/nuttx/nuttx.o -o test.o -lc
ld: warning: cannot find entry symbol _start; defaulting to 0000000000401140
ld: bin/src/ghdl_grt/ghwlib.c.o: in function `ghw_read_range(ghw_handler*)':
/home/jon/controlix-code/src/ghdl_grt/ghwlib.c:351: undefined reference to `sched_getstreams'
What am I missing?
Related
I'm going to assemble a program. But errors followed.
gcc -no-pie final.s -ldl -lm -lz -lrt -lpthread -lcrypt -lgmp -m64
/usr/bin/ld: error in /tmp/ccjXcZiN.o(.eh_frame); no .eh_frame_hdr table will be created.
/tmp/ccjXcZiN.o: In function `S_0x404C5A':
(.text+0x775): undefined reference to `have_libloaded'
/tmp/ccjXcZiN.o: In function `BB_73':
(.text+0x78f): undefined reference to `libhandle'
/tmp/ccjXcZiN.o: In function `BB_74':
(.text+0x79c): undefined reference to `load_library_errmsg'
/tmp/ccjXcZiN.o: In function `S_0x404CA0':
(.text+0x7bf): undefined reference to `have_libloaded'
collect2: error: ld returned 1 exit status
I know that there're some other libraries needed on the machine. But i can't search for the specific library name.
I have just seen this post: How to tell where the symbols are defined when linking C code ; and tried to run that approach (that is, I tried to look up via -Wl,-trace-symbol=foo during the linking command) on my code, which suffers from undefined reference - but the output is not much different from what is given as an example in that post:
/usr/bin/ld: main.o: reference to foo
/usr/bin/ld: ./libfoo.a(foo.o): definition of foo
/usr/bin/ld: ./libfoo.a(foo.o): reference to fputs
/usr/bin/ld: //lib/x86_64-linux-gnu/libc.so.6: definition of fputs
The thing is, I've manually added both -L and -l specifications to my command line, which I expect should pass - but they do not.
So what I am ultimately looking for, is a way to generate a log, that tells me, say:
/usr/bin/ld: main.o: reference to foo
/usr/bin/ld: ./libyoo.a(yooA.o): symbol foo looked up, not found
/usr/bin/ld: ./libyoo.a(yooB.o): symbol foo looked up, not found
/usr/bin/ld: ./libfoo.a(foo.o): definition of foo
... which, I hope, will make me understand a bit easier, which include and linker flag directories and files end up being scanned.
Is there a way to generate a log like this?
I'm learning C in college. And I wanted to try new things, so I decided to use the allegro Game library to create some stuff. I followed the tutorial, and everything went fine. I wrote a piece of code in the text editor and executed the commands provided by the tutorial and it compiled and run. (I'm on linux btw).
These are the commands:
gcc hello.c -o hello $(pkg-config allegro-5 allegro_font-5 --libs --cflags)
./hello
So, I understand that gcc is calling the gcc compiler and hello.c is the name of the source code file and -o hello specifies the name of the compiled file. but the next part is ambiguous and beyond my knowledge:
$(pkg-config allegro-5 allegro_font-5 --libs --cflags)
So can anyone explain what it means (it has something to do with linking). and if I remove that part the compiler returns these error codes:
/usr/bin/ld: /tmp/ccIQsEis.o: in function `main':
hello.c:(.text+0x2f): undefined reference to `al_install_system'
/usr/bin/ld: hello.c:(.text+0x34): undefined reference to `al_install_keyboard'
/usr/bin/ld: hello.c:(.text+0x45): undefined reference to `al_create_timer'
/usr/bin/ld: hello.c:(.text+0x4e): undefined reference to `al_create_event_queue'
/usr/bin/ld: hello.c:(.text+0x61): undefined reference to `al_create_display'
/usr/bin/ld: hello.c:(.text+0x6a): undefined reference to `al_create_builtin_font'
/usr/bin/ld: hello.c:(.text+0x73): undefined reference to `al_get_keyboard_event_source'
/usr/bin/ld: hello.c:(.text+0x85): undefined reference to `al_register_event_source'
/usr/bin/ld: hello.c:(.text+0x91): undefined reference to `al_get_display_event_source'
/usr/bin/ld: hello.c:(.text+0xa3): undefined reference to `al_register_event_source'
/usr/bin/ld: hello.c:(.text+0xaf): undefined reference to `al_get_timer_event_source'
/usr/bin/ld: hello.c:(.text+0xc1): undefined reference to `al_register_event_source'
/usr/bin/ld: hello.c:(.text+0xd4): undefined reference to `al_start_timer'
/usr/bin/ld: hello.c:(.text+0xe7): undefined reference to `al_wait_for_event'
/usr/bin/ld: hello.c:(.text+0x125): undefined reference to `al_is_event_queue_empty'
/usr/bin/ld: hello.c:(.text+0x13d): undefined reference to `al_map_rgb'
/usr/bin/ld: hello.c:(.text+0x16a): undefined reference to `al_clear_to_color'
/usr/bin/ld: hello.c:(.text+0x17e): undefined reference to `al_map_rgb'
/usr/bin/ld: hello.c:(.text+0x1ca): undefined reference to `al_draw_text'
/usr/bin/ld: hello.c:(.text+0x1cf): undefined reference to `al_flip_display'
/usr/bin/ld: hello.c:(.text+0x1e7): undefined reference to `al_destroy_font'
/usr/bin/ld: hello.c:(.text+0x1f3): undefined reference to `al_destroy_display'
/usr/bin/ld: hello.c:(.text+0x1ff): undefined reference to `al_destroy_timer'
/usr/bin/ld: hello.c:(.text+0x20b): undefined reference to `al_destroy_event_queue'
collect2: error: ld returned 1 exit status
And for the second part of the question, I tried to compile this code in code:blocks but it returns the same errors given by the compiler without the term: $(pkg-config allegro-5 allegro_font-5 --libs --cflags)
So, what configuration should I change in codeblocks so that it compiles well code using allegro libraries.
PS. I didn't include the source code intentionally as it adds no useful information to the question, only clutters it.
This is a Bash command-syntax feature which executes another command and then provides its output as a string. This idiom is being used here to programmatically provide command-line parameters to the gcc command. The pkg-config command is being executed, and it returns a string which becomes part of – is textually included in – the command-string for invoking gcc. (Which of course neither knows nor cares where its command-line parameters "come from.")
(Clever, huh?)
For example, try this:
echo $(ls)
You will be rewarded with a list of all the files in the current directory, concatenated as a string.
To elaborate on the answer by #Mike Robinson,
$(pkg-config allegro-5 allegro_font-5 --libs --cflags) will execute the command pkg-config and substitute the result. pkg-config is build utility that helps when compiling C programs. It's not specific to allegro, it is used by many C libraries.
In this particular case, pkg-config is called with the parameters allegro-5 allegro_font-5 --libs --cflags, which asks pkg-config "what are the compiler options (--cflags) and libraries (--libs) I need when compiling and linking with allegro?" Allegro consists of several modules, in this case you chose the main module 'allegro' and the font module 'allegro_font'. In both cases you're referring to major version 5 of allegro.
On your system, the result of the command is -I/usr/include/x86_64-linux-gnu -lallegro_font -lallegro. The meaning of these options is as follows:
-I/usr/include/x86_64-linux-gnu tells the compiler to add the path /usr/include/x86_64-linux-gnu to the header search path (because the allegro headers are located there)
-lallegro_font and '-lallegro` tells the linker to add the allegro_font and allegro libraries respectively. That also explains why you get all those undefined reference errors when you remove this - you are no longer telling the linker to add the allegro library, so it can't find all those functions anymore.
For my bachelor thesis I want to apply this algorithm proposed here: Binarization by Tissier
I cloned the repository and tried to run cd near-lossless-binarization in the corrsponding directory.
However there comes up an error I don't know how to solve.
cd near-lossless-binarization && make
gcc binarize.c -o binarize -ansi -pedantic -Wall -Wextra -Wno-unused-result -Ofast -funroll-loops -lblas -lm
/usr/bin/ld: /tmp/ccxe5d0J.o: in function `apply_regularizarion_gradient':
binarize.c:(.text+0xddc): undefined reference to `cblas_sgemm'
/usr/bin/ld: binarize.c:(.text+0xf9e): undefined reference to `cblas_sgemm'
/usr/bin/ld: /tmp/ccxe5d0J.o: in function `apply_reconstruction_gradient':
binarize.c:(.text+0x1059): undefined reference to `cblas_sgemm'
/usr/bin/ld: binarize.c:(.text+0x12fb): undefined reference to `cblas_sgemm'
/usr/bin/ld: binarize.c:(.text+0x1800): undefined reference to `cblas_sgemm'
/usr/bin/ld: /tmp/ccxe5d0J.o:binarize.c:(.text+0x1e71): more undefined references to `cblas_sgemm' follow
collect2: Error: ld gab 1 as end-Status returned
Seems like there is an issue inside the corresponding file.
I already opened an issue in the repo, but need answers pretty soon..
Hoped to find anyone with C experience here who may solve my problem.
Requirements named in the repo are fulfilled.
ld: foo.o: relocation R_X86_64_PC32 against undefined symbol `bar' can not be used when making a shared object; recompile with -fPIC
I recompile with -fPIC and it still produces this error.
Versions of your compiler and linker? Perhaps your problem is related to this bug, that seems to be fixed now: http://sources.redhat.com/bugzilla/show_bug.cgi?id=584?