cross gcc crti.o - gcc

I have followed the instructions at Cross linux from scratch for powerpc, but I can't get past the gcc-final stage due to an ld error crti.o: no such file or directory.
My tool chain is separated into two directories: /opt/builder/tools and /opt/builder/cross-tools, with Linux headers and eglibc in the first and cross-utilities in the second. Also I have created links /tools and /cross-tools for those directories.
I have tried /cross-tools/bin/powerpc-unknown-linux-gcc -print-search-path and there was a directory /opt/builder/tools/lib there in the "libraries" section. But gcc passes names of crt....o objects to ld without directory prefixes (I have used strace to find it out).
The crt....o files are good because, when I copied them to the directory with hello.c and compiled it, everything was ok.
Could you give some advice?
Thanks in advance,
Sergey Naumov.

The libc-provided crt files should be in $ROOT/$TARGET/lib/ (i.e., The gcc-compiled crt files will later be installed in $ROOT/lib/gcc/$TARGET/$GCC_VERSION/.

Related

g++: link to non-standard /usr/local

I have an OSX 10.7 computer with a non-administrator account, and was attempting to install the pre-compiled versions of gcc and g++ found here. I've attempted to use the answers presented in these questions (three different links) to compile some code with g++, to confusing avail. I have a folder structure like this:
~/code/:
usr/:
local/:
bin/ (3.6MB)
include/ (8.6MB)
lib/ (51MB)
libexec/ (49MB)
share/ (16MB)
c++/:
source/ (contains .cpp files)
g++ -v returns this:
code USER$ usr/local/bin/g++ -v
Using built-in specs.
COLLECT_GCC=usr/local/bin/g++
COLLECT_LTO_WRAPPER=/Users/USERNAME/code/usr/local/bin/../libexec/gcc/ x86_64-apple-darwin11.4.0/4.7.1/lto-wrapper
Target: x86_64-apple-darwin11.4.0
Configured with: ../gcc-4.7.1/configure --enable-languages=fortran
Thread model: posix
gcc version 4.7.1 (GCC)
An attempt at compiling a file that "#include"s only iostream:
$ usr/local/bin/g++ c++/source/test.cpp -o ex6
In file included from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/bits/postypes.h:42:0,
from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/iosfwd:42,
from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/ios:39,
from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/ostream:40,
from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/iostream:40,
from c++/source/ex6.cpp:1:
/Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/cwchar:46:19: fatal error: wchar.h: No such file or directory
compilation terminated.
I tried compiling with some flags recommended in one of the links mentioned, like this: (with all combinations of "usr/" to "usr/local/include/" and "usr/" to "/usr/local/lib" giving the same result (which is also the same as using no flags).
$ /Users/USERNAME/code/usr/local/bin/g++ source/ex6.cpp -I/Users/USERNAME/code/usr/local/include/ -L/Users/USERNAME/code/usr/local/lib/In file included from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/bits/postypes.h:42:0,
from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/iosfwd:42,
from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/ios:39,
from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/ostream:40,
from /Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/iostream:40,
from source/ex6.cpp:1:
/Users/USERNAME/code/usr/local/bin/../lib/gcc/x86_64-apple-darwin11.4.0/4.7.1/../../../../include/c++/4.7.1/cwchar:46:19: fatal error: wchar.h: No such file or directory
compilation terminated.
In short, I'm having trouble understanding what the answers in the links provided are saying to do. I saw reference to a specs file, which I could find no specific information for, and "-Wl,-rpath,$(DEFAULT_LIB_INSTALL_PATH)", for which I couldn't figure out what I was supposed to substitute for "DEFAULT_LIB_INSTALL_PATH".
What should I do to point the downloaded g++ compiler to its own files without placing them in their default location, as I do not have administrative capabilities on this account?
I will provide any information as necessary.
It looks like you don't have required header files. You need to install Command Line Tools from Apple Developers site (free registration needed). The problem is that you don't have administrator account. I suggest that you ask the administrator to install the tools for you. If it is not possible you could try to extract the contents of downloaded package (DevSDK.pkg) to your local directory (Pacifist can do that) and pass the path with the missing headers to your compiler. I haven't tried that though.

Link with relative paths in gcc

I will use a simplified example to explain my case.
I have two libme.so files which have different implementations and I already verified that they can work in a single design at the same time. One is located at ./root/v1/ and the other one is located at ./root/v2/
My "main" .so file is linked with those 2 libme.so files and is located at ./root/libtest.so
Now I have the requirement to make the things relocatable. That is, if I copy the entire "root" directory to another location or even another machine (assuming binary compatible), things should still work fine.
My question is, to make this work, what gcc command line should I use to build libtest.so?
I've tried the following two:
(1) (assuming I'm in "root" directory)
>gcc -shared -o libtest.so ./v1/libme.so ./v2/libme.so
This will make libtest.so has those 2 link dependencies both with absolute paths. This can be verified via ldd:
>ldd libtest.so
/home/design/root/v1/libme.so
/home/design/root/v2/libme.so
Obviously the paths are fixed. So once I relocate the "root" directory, it cannot find libme.so at runtime. Note setting LD_LIBRARY_PATH doesn't work in this case since the path from ldd is absolute path. The runtimer loader will not search LD_LIBRARY_PATH to find libme.so.
(2)
>gcc -shared -o libtest.so -lme -L./v1 -L./v2
This will work only if we have a single version of libme.so. In this case, the version in ./v2 will not get linked in. The same issue exists for -rpath.
Given that, what other options do I have?
Note there are some restrictions:
(1) cannot rename libme.so to other names such as libme_v1.so
(2) libtest.so has to link in both versions of libme.so
Teppic is right. This turned out to be an issue only happening on one of my machines. Switching to another RHEL5.8 machine and I'm all set. It looks like the original machine installed a linker customized by someone.

Why is my shared library not found?

I'm trying to compile an example program that links to the shared library produced by Sundown. I'm compiling the program like so.
$ gcc -o sd sundown.c -L. -lsundown
Yet, when I run it I get the following error.
./sd: error while loading shared libraries: libsundown.so: cannot open shared object
file: No such file or directory
The output of ls is.
$ ls
libsundown.so libsundown.so.1 sundown.c sd
Why is the shared library not found by ld?
Short solution:
add . (or whatever it is from your -L flag) to your LD_LIBRARY_PATH. When you run sd, it'll look for libraries in the standard places and the LD_LIBRARY_PATH. Note that since you've added ., this will only work if you run sd from the same directory libsundown.so is in.
I plan on distributing the compiled binary. How can I do so that the library can be distributed without forcing people to edit their LD_LIBRARY_PATH?
You should install libsundown.so in one of the standard places, like /usr/lib or /usr/local/lib. You can do that with an installer or a make file, or something as simple as a INSTALL or README that tells the user to stick the libraries there and ensure the permissions are set to something sensible.
On Centos systems with /usr/lib and /usr/lib64, if you install 64-bit libs manually into /usr/lib then at runtime, the library may not be visible even though at build time it is visible (I used autotools and it was able to find my zopfli library from /usr/lib without any problem). When I execute the my_binary that links to /usr/lib/libzopfli.so.1 I got
libzopfli.so.1 => not found
After moving libzopfly.so.1 from /usr/lib to /usr/lib64, then everything works fine.

ld: After successful linking shared lib not found on execution

I am currently working on a simple data synchonizer in a mixture of Fortran and C/C++ by using OpenMPI libraries. The synchonizer compiles and links correctly, as far as I can see:
f95 -o fortran_mpi_test *.o -L/usr/lib/gcc/x86_64-redhat-linux/4.1.1/
-L/usr/lib64/openmpi/1.4-gcc/lib/ -lmpi -lmpi_cxx -lstdc++
But when I execute the resulting executable on the same machined I get an error stating that one of the shared libraries is not found. That is confirmed by ldd.
Nevertheless the missing library libmpi_cxx.so.0 is located in one of the specified folders.
Could anyone give me a hint what I could have done wrong?
Check your environment variables. If your LIBRARY_PATH, LD_LIBRARY_PATH or similar vars have gotten out of sync or set to silly values you might not be searching the same directories for static libraries as you do for dynamics.
Also check out the ld.so manpage

Using Boost with Cygwin on Windows

This shoud be a simple problem for users more advanced than I am. :-)
How do I use the boost library with cygwin on windows?
I am programing with g++ using cygwin on a winxp machine.
I need modified Bessel functions of the second order, so I downloaded the latest version of the boost library and installed it in
'c:\cygwin\lib\boost_ 1_ 38_0\' folder.
I am trying to run the "example.cpp" program from the "getting started" section of their website:
http://www.boost.org/doc/libs/1_35_0/more/getting_started/unix-variants.html
I am compiling from the directory where I created the example file using a simple Bash shell command line: 'g++ -Wall example.cpp'
I keep getting the message:
"boost/lambda/lambda.hpp: no such file or directory"
I tried every possible combination of -L, -l, -I options in the command line to include the directory, to no avail. Also tried to add the folder in the PATH line of my windows system.
How do I link to the /boost directory and ALSO to all subdirectories? The header file 'lambda.hpp' is calling other header files in subdirectories.
You're probably not that familiar with C++ yet? It seems you are confusing terms.
C++ programs are built in two steps: compiling and linking. In the first step, each source file (typically called .cpp) is handled individually. Each .cpp file usually uses multiple headers, so the compiler first inserts those - literally. That's why it's called #include.
In the second step, the linker takes all the compiled .cpp files together and builds your final program. Some of those compiled .cpp's might have been bundled together before, in which the bundle is called a library.
Boost is a collection of headers and .cpp files. So, both compiler and linker might need to find the Boost directories. From your error message, it's clear that the compiler step is the problem. The linker does not need headers anymore.
The compiler will see the #include <boost/lambda/lambda.hpp> instuction. That means it needs to know where that first-level boost directory is found. I would guess at this point that the path would be /lib/boost_ 1_ 38_0/include (there's always the find / -name lambda.hpp shotgun appraoch)
If you are not utterly wedded to cygwin, you should take a look at http://nuwen.net/mingw.html which gives you a complete MinGW C++ installation with all the libraries (such as Boost) set up for you.
Edit: I should make it clear you can use this MinGW installation in addition to Cygwin, not as a replacement. Just make sure the MinGW bin directory appears in your PATH before the Cygwin one.
I think you need -I /lib/boost_1_38_0 - although that's a pretty unusual place to put it. You'll have to let us know how you installed it, did you just unzip it in the location you said, or did you run the makefiles? I assume that since you gave a windows path you didn't install it within cygwin - which you probably should do. The instructions in the getting started guide for unix should help - although don't download a prebuilt bjam - it needs to be built with cygwin.
But if you're not very familiar with cygwin (or unix in general) I think you might find it easier to use a native windows tool - as in Neil Butterworth's answer.
Thank you all for the information, it's a nice introduction to the use of libraries with cygwin.
Daniel was right. While any variation gives an error, the following line (using caps i) does the trick:
g++ -Wall -I /cygdrive/c/cygwin/lib/boost_1_38_0/ example.cpp -o example
I will also check MinGW in the next few days.
p.s. I simply downloaded and unzipped boost in that folder, but since I am only using header files I probably won't need to compile with cygwin. [The boost version included with cygwin was 1.33, which does not seem to have Bessel functions.]
This is on win7 cygwin64 g++ 5.4, and boost-1.64.7z on 2017-7. Google doesn't show any useful result for getting started for boost on windows (is boost out of fashion?).
By experimenting, I managed to compile and run a boost graph sample program as follows:
:: g++ 5.4 in c:\cygwin64
:: 7z extract boost download in c:\tools\boost\boost164
> set BOOST_ROOT=c:\tools\boost\boost164
> setx BOOST_ROOT c:\tools\boost\boost164 -m
> cd %BOOST_ROOT%
> bootstrap.sh gcc (the bat files doesn't work)
> b2.exe
...failed updating 58 targets...
...skipped 18 targets...
...updated 1123 targets...
:: Lots of example here (not ranked highly by google)
> mklink /D eg %BOOST_ROOT%/libs/graph/example
:: Compiled and run [maxflow code using boost library][1]
:: http://vision.csd.uwo.ca/code
> unzip ; vi Makefile
CPPFLAGS = -I %BOOST_ROOT%/
LDFLAGS = -L%BOOST_ROOT%/stage/lib
> make
> set PATH=%PATH%;%BOOST_ROOT%/stage/lib
> maxflow.exe
Flow = 6

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