I am trying to create executable using some libraries.
My GCC command is :-
gcc -fPIC -DLINUX testdenpli /verilog/libdenpli.so -L/local/test/dir/ testpli.c
I have my library with symbols at path '/local/test/dir/'
Error:-
libdenpli.so: undefined reference to `ktlTcl_InitStubs'
libdenpli.so: undefined reference to `ktlitclStubsPtr'
I have the libraries with above symbols at path "'/local/test/dir/" .. But still seeing the issue.
Any one please help.
The error message says that libdenpli.so requires linking another shared library that provides symbols ktlTcl_InitStubs and ktlitclStubsPtr.
Find the shared library that provides those symbols using the following command:
for so in $(find /local/test/dir -name "*.so" -o -name "*.so.*"); do
nm --defined-only --dynamic $so 2>/dev/null | grep -q 'ktlTcl_InitStubs|ktlitclStubsPtr' && echo $so;
done
Then add that library into your linker command line:
gcc -Wall -Wextra -fPIC -DLINUX -o testdenpli testpli.c /verilog/libdenpli.so <full-path-to-found-library>
What is the name of the library containing the symbols? You need to include -lNAME to your compilation.
In general,
gcc file.c -o file -L/path/to/libs -lNAME
Note, the prefix "lib" and the suffix ".so" needn't be mentioned.
Related
I am a Unix/Linux newbie who is trying to run a shell script written by a person who left no documentation and has since demised. This script contains line:
./search $opt1 $arg1 < $poly 2>&1 | tee $output
Which is trying to get the file $poly and call program ./search and divert the output to $output.
When I get to this line, I am given message: ./search: cannot execute binary file: Exec format error
search is a C program called from the script and is in the same folder as various other C programs to do with this project. Script and C programs were developed and originally executed on a Unix/Linux box which is no longer available, so I have been asked to try to resurrect this project but under Windows using gcc in NetBeans and cygwin.
The message : ./search: cannot execute binary file: Exec format error is most likely to do with the fact there is no executable file for search. When I try to build the C programs I get the following output:
C:\cygwin64\bin\make.exe -f Makefile
gcc -ansi -g -c cbuild.c
gcc -ansi -g -c complex.c
gcc -ansi -g -c mylib.c
gcc -ansi -g -c poly.c
gcc -ansi -g -c real.c
gcc -ansi -g -c zero.c
gcc -lgmp -lm -lrt -o cbuild cbuild.o complex.o mylib.o poly.o real.o zero.o
real.o: In function `rabs':
/cygdrive/c/../progs/real.c:9: undefined reference to `__imp___gmpf_abs'
/cygdrive/c/../progs/real.c:9:(.text+0x1e): relocation truncated to fit: R_X86_64_PC32 against undefined symbol `__imp___gmpf_abs'
real.o: In function `radd':
I assume that R_X86_64_PC32 refers to the environment I am using. I am using a 64 bit version of Netbeans with gcc 5.4.0 in a 64 bit version of cygwin on Windows 10.
Can anyone advise what I must to to resolve this so that I can build the C programs?
The problem is this:
gcc -lgmp -lm -lrt -o cbuild cbuild.o complex.o mylib.o poly.o real.o zero.o
By default, the linker will link libraries and objects in the order specified on the command line, and, when linking a library, will only include symbols needed by things before it on the command line. Since -lgmp is first, there are (as yet) no outstanding symbols (except main), so nothing is included from the library. When later objects need the symbols from it, they won't see them.
Change the order to
gcc -o cbuild cbuild.o complex.o mylib.o poly.o real.o zero.o -lgmp -lm -lrt
and it should work. Alternately, use the -Wl,--as_needed linker option to get the linker to remember earlier libraries and relink them if more symbols from them are referenced by later object files (requires a recent version of the GNU linker -- I have no idea if it works with cygwin).
This kind of misordering is usually a symptom of a broken Makefile. The normal Makefile structure has a bunch of variables that are set to control the default rules that know how to compile source files and link object files. The two variables relevant for linking are LDFLAGS and LDLIBS, and the difference is that LDFLAGS comes before all the object files on the command line and LDLIBS comes after all the object files.
So in order to make things work, you need to ensure that all of the -l options and other libraries are in LDLIBS:
LDLIBS = -lgmp -lrt -lm
and NOT in LDFLAGS
I have static library lib.a and in all tutorials using:
gcc -o main main.o -L. -lib
But I cant, I have errors:
/usr/bin/ld: cannot find -lib
collect2: error: ld returned 1 exit status
I need to use:
gcc -o main main.o -L. -lib.a
Why? What should I do to repair it ?
From the documentation of gcc -l:
-llibrary:
The linker searches a standard list of directories for the library, which is actually a file named liblibrary.a. The linker then uses this file as if it had been specified precisely by name.
...
The only difference between using an -l option and specifying a file name is that -l surrounds library with ‘lib’ and ‘.a’ and searches several directories.
So you cannot use -l with a library named 'lib.a'. Use 'lib.a' without the -l to include it. Of course, you cannot use -L then to set the directories to be searched for this particular library.
Do you have the error with this line ?
gcc -o main main.o -L. -llib
As MicroVirus found in the documentation, you will have to rename your library in liblib.a to use my previous line or just pass your library to gcc like a simple file.
I'm trying to compile my project and I use the lib ncurse. And I've got some errors when compiler links files.
Here is my flags line in Makefile:
-W -Wall -Werror -Wextra -lncurses
I've included ncurses.h
Some layouts :
prompt$> dpkg -S curses.h
libslang2-dev:amd64: /usr/include/slcurses.h
libncurses5-dev: /usr/include/ncurses.h
libncurses5-dev: /usr/include/curses.h
prompt$> dpkg -L libncurses5-dev | grep .so
/usr/lib/x86_64-linux-gnu/libncurses.so
/usr/lib/x86_64-linux-gnu/libcurses.so
/usr/lib/x86_64-linux-gnu/libmenu.so
/usr/lib/x86_64-linux-gnu/libform.so
/usr/lib/x86_64-linux-gnu/libpanel.s
And here are my erros :
gcc -W -Wall -Werror -Wextra -I./Includes/. -lncurses -o Sources/NCurses/ncurses_init.o -c Sources/NCurses/ncurses_init.c
./Sources/NCurses/ncurses_init.o: In function `ncruses_destroy':
ncurses_init.c:(.text+0x5): undefined reference to `endwin'
./Sources/NCurses/ncurses_init.o: In function `ncurses_write_line':
ncurses_init.c:(.text+0xc5): undefined reference to `mvwprintw'
./Sources/NCurses/ncurses_init.o: In function `ncurses_init':
ncurses_init.c:(.text+0xee): undefined reference to `initscr'
collect2: error: ld returned 1 exit status
Thanks a lot
You need to change your makefile so that the -lncurses directive comes after your object code on the gcc command line, i.e. it needs to generate the command:
gcc -W -Wall -Werror -Wextra -I./Includes/. -o Sources/NCurses/ncurses_init.o -c Sources/NCurses/ncurses_init.c -lncurses
This is because object files and libraries are linked in order in a single pass.
In C++ , I fixed it just by linking the ncurses library .
Here is the command :
g++ main.cpp -lncurses
I got flags to correct order by using LDLIBS variable:
ifndef PKG_CONFIG
PKG_CONFIG=pkg-config
endif
CFLAGS+=-std=c99 -pedantic -Wall
LDLIBS=$(shell $(PKG_CONFIG) --libs ncurses)
man gcc | grep -A10 "\-l library"
-l library
Search the library named library when linking. (The second alternative with the library as a separate argument is only for POSIX
compliance and is not recommended.)
It makes a difference where in the command you write this option; the linker searches and processes libraries and object files
in the order they are specified. Thus, foo.o -lz bar.o searches
library z after file foo.o but
before bar.o. If bar.o refers to functions in z, those functions may not be loaded.
I'm trying to compile my code with a DLL i made and I get the error below when i write ./prog
./prog: error while loading shared libraries: libctest.so.1: cannot open shared object file: No such file or directory
I followed the tutorial here and my mono app has no problem loading the dll and calling the functions. The key parts of the tutorial were
gcc -Wall -fPIC -c *.c
gcc -shared -Wl,-soname,libctest.so.1 -o libctest.so.1.0 *.o
mv libctest.so.1.0 /opt/lib
ln -sf /opt/lib/libctest.so.1.0 /opt/lib/libctest.so.1
ln -sf /opt/lib/libctest.so.1.0 /opt/lib/libctest.so
My C# code does
[DllImport("path/to/CDLL", CallingConvention = CallingConvention.Cdecl)]
public static extern void test();
I built with
gcc -Wall -L/opt/lib main.c -lctest -o prog
This is the first thing i changed. prog.c to main.c. From there I simply run with ./prog to get the error at the top of this question. I do this as root so there shouldn't be permission issues. I also chmod 755 the so's. What am I doing wrong? This is opensuse. I had to create the /opt/lib so I am thinking this path isn't registered where it should be
The dynamic linker ld.so will not look in /opt/lib by default when attempting to resolve library dependencies. You have to tell the linker about the non-standard library directories or add the /opt/lib path to your prog binary.
eg
LD_LIBRARY_PATH=/opt/lib ./prog
or, link prog with the -rpath linker option. This provides an additional path for the linker to search when resolving locations of shared objects.
gcc -Wall -L/opt/lib -Wl,-rpath,/opt/lib main.c -lctest -o prog
You can use the ldd command on a binary to show the locations of shared libraries.
ldd prog
This will currently show that libctest.so cannot be found. With an additional search path, the following command should show that all libraries are resolved:
LD_LIBRARY_PATH=/opt/lib ldd prog
I need to compile an old application whose tarball only contains *.c and *h, ie. no Makefile. The root directory contains the application, and a sub-directory contains a library the application needs.
My make/Makefile knowledge isn't great, and I was wondering what the easiest way would be to compile this application + library.
Thank you.
Edit: Using this script...
# cat compile.bash
#!/bin/bash
cd mylib
for cfile in *.c; do
ofile=$(echo "$cfile" | sed 's#.c$#.so#')
gcc -shared -c "$cfile" -o "$ofile"
done
cd ..
gcc *.c -I mylib -L mylib -mylib -o myapp
... I notice that each *.c file in mylib/ is compiled into a *.so file instead of compiling each into an object file and building a single .so file, and I get tons of warnings and errors, eg.
unzip.c: In function âunzipâ:
unzip.c:991: warning: format not a string literal and no format arguments
gcc: unrecognized option '-mylib'
file_util.c: In function âfile_moveâ:
file_util.c:98: error: âerrnoâ undeclared (first use in this function)
I don't know how to compile the library, and then compile the application without error/warning.
No need to use a for loop or generate intermediate object files:
(cd mylib && gcc -shared -fPIC -o libfoo.so *.c) && \
gcc -Imylib -o app *.c mylib/libfoo.so
Compile the library:
cd libfoo
for cfile in *.c; do
ofile=$(echo "$cfile" | sed 's#.c$#.so#')
gcc -shared -c "$cfile" -o "$ofile"
done
After this, you should have a libfoo.so file in libfoo/. Then, compile the program (Don't forget to cd back):
gcc *.c -I libfoo -L libfoo -lfoo -o application
The easiest is probably to get an IDE to do the build for you. Netbeans for one will create a Makefile so you can then build the project independently of the IDE.