My program uses the GNU Multiple Precision Arithmetic Library to deal with numbers of an arbitrary size. I successfully compile it using GCC with:
gcc main.c -o diff -g -lgmp
However, when I try to use the MinGW crosscompiler compiler, I get the following error:
i686-w64-mingw32-gcc main.c -o diff.exe -g -lgmp
main.c:3:46: fatal error: gmp.h: No such file or directory
#include <gmp.h>//For files of arbitrary size
I then tried to tell it exactly where the header file was:
i686-w64-mingw32-gcc main.c -o diff.exe -I/usr/include -g -lgmp
/usr/lib/gcc/i686-w64-mingw32/4.9.2/../../../../i686-w64-mingw32/bin/ld: cannot find -lgmp
collect2: error: ld returned 1 exit status
Ok, so I figure now it successfully found the header, but cant find the library. So I tried again:
i686-w64-mingw32-gcc main.c -o diff.exe -I/usr/include -g -L/usr/lib -lgmp
/usr/lib/gcc/i686-w64-mingw32/4.9.2/../../../../i686-w64-mingw32/bin/ld: cannot find -lgmp
collect2: error: ld returned 1 exit status
I guess I need to specify the exact files to use, so I tried this:
i686-w64-mingw32-gcc main.c -o diff.exe -I/usr/include -g /usr/lib/libgmp.so
/usr/lib/libgmp.so: file not recognized: File format not recognized
collect2: error: ld returned 1 exit status
So, I honestly don't know what to do and I'd really really appreciate your help.
First, a disclaimer: the cross-compiler you are using is neither distributed by, nor supported by MinGW.org, whom I represent; if you are looking for a pre-compiled solution, you should seek it from the distributor of the specific cross-compiler itself.
That said, I can offer the following insight, (which will apply, in general, to any cross-compiler): the headers you find in /usr/include, or in /usr/local/include, and the libgmp.so which you find in /usr/lib, or in /usr/local/lib, are intended for use with your native platform compiler. They are not suitable for, and cannot be used with your MinGW cross-compiler; attempting to do so will surely never work. Thus, you have two options:
Ask your cross-compiler distributor to provide a pre-compiled copy of gmp.dll, (or at the very least, a compatible import library, although you may need the gmp.dll to distribute with your own application anyway), and any associated header files, and/or equivalent statically linkable library, for use with your cross-compiler.
Use your cross-compiler to build gmp.dll yourself, then install it, its associated headers, and perhaps also its associated import library and/or equivalent statically linkable library, into the same prefix-path as the cross-compiler itself.
Related
I am trying to build a shared library lib_test.so from 'test.c' & test.exp files. This lib_test.so file will be used as a extension to another application.
The application doc specifies generation of tle lib_test.so file directly in a single pass by the following command:
`gcc -q64 -o lib_test.so test.c -bM:Sre -bE:test.exp -bnoentry`
But my requirement is to build the library in two passes:
Compile to generate test.o file using gcc command.
Link to generate the library lib_test.so using ld command.
I tried this as follows:
Executed compile step as follows: gcc -q64 -c -o test.o test.c.
Create lib_test.so as follows: ld -bM:Sre -bE:test.exp -bnoentry -o lib_test.so test.o
But it is not generating a proper lib_test.so file.
I am using Ubuntu 16.04 LTS 64-Bit with latest GCC
Can you please suggest the correct way to split the process into two passes...
Thanks & Regards.
You rarely ever want to use ld to perform the linking. The gcc frontend does the better job of setting the right flags etc. So, use gcc.
i.e. Instead of
ld -bM:Sre -bE:test.exp -bnoentry -o lib_test.so test.o
do
gcc -bM:Sre -bE:test.exp -bnoentry -o lib_test.so test.o
in your second step.
The big difference between linking with the GCC frontend program gcc and with the actual linker ld is that the GCC frontend adds a few libraries to be linked with. Most notably the GCC runtime library (-lgcc_s or -lgcc) and the actual standard C library (-lc).
When you invoke ld directly you do not tell it to link with those libraries.
There might also be other libraries and flags the GCC frontend passes to ld without your knowledge. For the "one pass" build, pass the flag -v to gcc for verbose output and see what arguments, flags and libraries it uses.
When I try to build the following program:
#include <stdio.h>
int main(void)
{
printf("hello world\n");
return 0;
}
On OS X 10.6.4, with the following flags:
gcc -static -o blah blah.c
It returns this:
ld: library not found for -lcrt0.o
collect2: ld returned 1 exit status
Has anyone else encountered this, or is it something that noone else has been affected with yet? Any fixes?
Thanks
This won’t work. From the man page for gcc:
This option will not work on Mac OS X unless all libraries (including libgcc.a) have also been compiled with -static. Since neither a static version of libSystem.dylib nor crt0.o are provided, this option is not useful to most people.
Per Nate's answer, a completely static application is apparently not possible - see also man ld:
-static Produces a mach-o file that does not use the dyld. Only used building the kernel.
The problem in linking with static libraries is that, if both a static and a dynamic version of a library are found in the same directory, the dynamic version will be taken in preference. Three ways of avoiding this are:
Do not attempt to find them via the -L and -l options; instead, specify the full paths, to the libraries you want to use, on the compiler or linker command line.
$ g++ -Wall -Werror -o hi /usr/local/lib/libboost_unit_test_framework.a hi.cpp
Create a separate directory, containing symbolic links to the static libraries, use the -L option to have this directory searched first, and use the -l option to specify the libraries you want to use.
$ g++ -Wall -Werror -L ./staticBoostLib -l boost_unit_test_framework -o hi hi.cpp
Instead of creating a link of the same name in a different directory, create a link of a different name in the same directory, and specify that name in a -l argument.
$ g++ -Wall -Werror -l boost_unit_test_framework_static -o hi hi.cpp
You may also try LLVM LLD linker - I did prebuilt version for my two major OSes - https://github.com/VerKnowSys/Sofin-llds
This one allows me to link for exmple: "Qemu" properly - which is impossible with ld preinstalled by Apple.
And last one is - to build GCC yourself with libstdc++ (don't).
I'm trying to compile and link some .c file. I have been using Eclipse IDE for C/C++ developers, and in my local machine i can compile without problems. However, when i try to compile and link the same file in a RedHat OS (gcc version is 4.9.2-6 in this OS) i'm having problems. I get some warnings at compile time, but those are fine, i think, i just ignored and the application still runs fine. Here are the commands i executed and the associated output:
gcc -O0 -g3 -Wall -c -fmessage-length=0 -std=c99 -MMD -MP -MF"example.d" -MT"example.d" -o "example.o" "example.c"
warning: suggest parentheses around assignment used as truth value [-Wparentheses]
warning: implicit declaration of function ‘wait’ [-Wimplicit-function-declaration]
This generates two files, example.d and example.o. Then, i try to link them, without luck, with the following command:
gcc -Xlinker -L/usr/lib -lrt -static -pthread example.o -o example
/usr/bin/ld: cannot find -lrt
/usr/bin/ld: cannot find -lpthread
/usr/bin/ld: cannot find -lc
collect2: error: ld returned 1 exit status
The commands are taken directly from the ones that Eclipse generates, and work just fine in my local computer (Ubuntu OS) but not in the RedHat environment. The last command didn't work, with and without the -L option. I suppose the directory in -L is fine, as i run, for example,
locate libpthread.so
And one of the locations i get is /usr/lib (also /usr/lib64, but neither work).
Any help will be greatly appreciated!! :)
If you try to link a static executable, it will look for the *.a versions of the libraries, not what you usually want. Remove the -static flag. Or you can install the static libraries if you really want to. It also should not be necessary to add -L/usr/lib explicitly.
I am working with c++ code for a physics simulation, which uses a lot of external libraries (like GSL and cern`s ROOT). Trying to recompile project I encountered problems with linking. When running compilation of final file via:
g++ -fno-inline -O2 -fpic -o main.out ${ROOTINCS} main.o ext.o ${ROOTLIBS} $(objects2)
with :
objects2= many .o files made by us
ROOTLIBS=-L/usr/local/lib/root -lTree -lRIO -lNet -lHist -lMathCore -lCore -lGraf -lGraf3d -lGpad -lMatrix -lThread -lCint -lPhysics -lPostscript -lRint -lSpectrum -lg
ROOTINCS=-pthread -m64
I get annoying error:
/usr/bin/ld: /usr/local/lib/root/libHist.so: undefined reference to symbol 'gRandom'
/usr/local/lib/root/libMathCore.so: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
The problem is nm -C run on libMathCore states 'gRandom' is declared there. Also -lMathCore is present in my command line.
When I run ld to check if it understands the flag:
ld -L/usr/local/lib/root -lMathCore --verbose 2>/dev/null
it does not complain and tries to link properly.
According to https://stackoverflow.com/a/24675715/3602168 order of libraries is correct in my linking (libHist uses libMathCOre and therefore is stated first).
Compilation runs under g++ 4.8.2 on ubuntu 14.04, 64 bit
Converting comment to answer:
Have you tried moving $(objects2) before ${ROOTLIBS}? I think the issue may be that you have libraries specified before the object files that use them.
I'm trying to compile a makefile which includes the following line:
gcc -I. -I/home/usr/Documents/MTV/include -ggdb3 -Wall -O2 -o ascii2bin.c \
-L. -L../lib -lmatrix -lseq_io -lpic -lm
And this is what I get:
../lib/libmatrix.a: file not recognized: File format not recognized
collect2: ld returned 1 exit status
Any idea on what might happen to libmatrix.a? How can I read what's inside libmatrix.a? I tried using the 'ar -t' command, but it also says file format not recognized.
The project was compiled on Cygwin before by others, and now I'm using ubuntu gcc to try to redo it, could this be the problem?
A library file built for cygwin will not work on linux.
The library itself must be recompiled from source to match the details (ABI, dynamic system library dependencies, etc) of the system on which it is intended to be used.
Cygwin tries to be source compatible with Linux, so if you have the source rebuilding may be straightforward. But it is not binary-compatible, and libraries are basically binary building blocks with metadata to permit linking them together.