GCC installation prefix under Linux - linux

What is the recommended installation prefix for GCC under Linux (say default installation of Ubuntu)?
Would it be the default /usr/local of just /usr?
I am asking because I ran into a problem similar to this one.
So, is it really a mistake (not recommended) to install GCC to /usr/local
Thanks.

From official gcc instalation documents:
--prefix=dirname
Specify the toplevel installation directory. This is the recommended way to install the tools into a directory other than the default. The toplevel installation directory defaults to /usr/local.
We highly recommend against dirname being the same or a subdirectory of objdir or vice versa. If specifying a directory beneath a user's home directory tree, some shells will not expand dirname correctly if it contains the `~' metacharacter; use $HOME instead.
More at: http://gcc.gnu.org/install/configure.html

Related

How to make Cmake globally available

I just installed Cmake from git clone wget http://www.cmake.org/files/v2.8/cmake-2.8.3.tar.gz in a new folder on a Linux server. The compilation worked but cmake command is not recognized from other paths. Should I copy the entire contents of cmake-2.8.0 folder to usr/local/bin? Or is the contents of bin folder that need to be copied?
Thanks
On Linux and other Unix-based systems, a common arrangement is to install packages to /opt and add relevant entries to the PATH environment variable to make them available. This is intended for packages not provided by the native package manager or distribution. By choosing an appropriate directory structure, this can be done in a way which also allows different versions to be installed simultaneously and the user can pick which one they want by adding the relevant directory to the PATH.
For the specific case of CMake asked about in the question, you can use a directory structure like /opt/cmake/<version> and then add the relevant /opt/cmake/<version>/bin directory to your PATH (e.g. /opt/cmake/3.8.2/bin for the 3.8.2 CMake release). You can even just download the official pre-built CMake tarballs, unpack them and move the top level directory into the /opt/cmake area as the particular version you downloaded. I've used this successfully on Linux, MacOS and Solaris, as I'm sure have many others.
Note that once you've run CMake on a particular source tree, the cmake executable doesn't need to be on the PATH any more. If cmake needs to be re-run, the build will do so itself and it records the full path to the cmake executable in its own cache, so the PATH isn't even consulted (this is essential in ensuring the same version of CMake continues to be used for all builds regardless of the PATH, since PATH can change between login sessions, etc.). You would only need cmake on your PATH if you intend to invoke cmake manually or for the first time you run it on a source tree, but in both of these cases you can always just use the full path to the cmake executable if you preferred.
I should also add that the entire set of files provided in the CMake package are required, not just the bin directory. CMake makes extensive use of files in its other directories, such as the various modules it comes with. If you are building CMake from source, you may want to build the package target so you get a relocatable tarball or similar which will contain everything that should be included when you provide a CMake package on your system.
After the build, use 'sudo make install'. This will make sure the correct libraries and binaries are copied to their proper places.
Usually this will install the binary to /usr/local/bin.
Make sure the PATH variable has this included.
sudo make install did not copy to /usr/local/bin/ for some reason, so I copied the content of CMAKE /bin. to usr/local/bin an it worked.
cp –a bin/. /usr/local/bin/

RPM-BUILD- Spec file Understanding

I am new in Linux. I want to create a rpm from tar.gz by rpmbuilder. But I am little bit confused about
make PREFIX=/usr/ DESTDIR=%{?buildroot} install
I want to know what is happening by this. If I don't give the PREFIX and DESTDIR what will be happened.
DESTDIR=%{?buildroot} is required for installing to BUILDROOT folder. BUILDROOT folder must contain the same hierarchy of files that should exist after installing of the package, that is why we should install to it.
PREFIX=/usr/ is used for installing not to /usr/local/ but to /usr/, so your binaries will appear in /usr/bin/ folder, not in /usr/local/bin/. Note that this /usr/ folder will exist in BUILDROOT during the work of rpmbuild (because of point 1).

Debian / Ubuntu package installed in root as default

Created a simple debian/ubuntu package with some library files (*.so).
Works fine except, it installs them as default in the root path "/".
Since I've recreated my Makefile to output to $DESTDIR/ instead of "the usual" directory that I provide in the Makefile, when compiling from source, how do I now set the path of where the files should be installed now? I know there are several choices when using dh_make to create the package, "s" being the default one. Still, can't seem to find anything on where to tell dpkg to put the installed files.
Secondly, a Deb Library package containing only ".so" files should still be a "Single binary" since I gather that using the Library is for development purposes? Since this is a library, I just wanna make sure that's not the cause of the files being installed in the wrong location. What I mean is .so files and header files installation?
What I've used:
dh_make -e my#email.com -f ../myfile-1.0.tar.gz
dpkg-buildpackage -rfakeroot
and some configurations set i debian/control, $DESTDIR in Makefile.
Seems that it was fairly simple, yet very confusing. This works, not sure if there is a better solution.
In my makefile I have a few variables
InstallTo = /usr/lib
install:
mkdir -p $(DESTDIR)$(InstallTo)
cp $FILE_TO_COPY $(DESTDIR)$(InstallTo)
This way it will create the directory tree inside the *.deb file. I had some trouble using /usr/local/lib instead of /usr/lib/ and rmdir complained when trying to delete it and it had no files (just directories). Not sure why, but changed it to /usr/lib instead.
Since someone voted this up, I'm guessing someone were also looking for the answer and this is my solution. Perhaps someone can provide a better one if there is one.
Just a note, $DESTDIR variable is the variable that dh_make suggest the user to use in our Makefile. It's the path to where dpkg will build the program and where it will install it so it can be included in the .deb file.

What actually is $RPM_BUILD_ROOT?

In the process of building an RPM package, I have to specify the BuildRoot and later will be used in %install which invovles $RPM_BUILD_ROOT. I always think that $RPM_BUILD_ROOT is the fake installation for RPM to perform packaging. Then, at install time using the RPM package, it will install into actual location. For example:
$RPM_BUILD_ROOT/usr/bin
I thought that $RPM_BUILD_ROOT is for the packaging process only, and in some ways RPM can distinguish the $RPM_BUILD_ROOT and the actual install location when the user performs "rpm -ivh package.rpm" will be /usr/bin.
But recently upon reading some documents, it is suggested that $RPM_BUILD_ROOT is the actual location which will be installed, and the $RPM_BUILD_ROOT is specified by user with the setting of environment variable $RPM_BUILD_ROOT in order to let the users install the package in their desire locations. Otherwise, $RPM_BUILD_ROOT will be null and it will install into the default location. In the above case, it is /usr/bin . Thus, $RPM_BUILD_ROOT is not just for packaging or "fake installation" process, but is a way for user to define install location, similar to select folder location in Windows.
I don't know my thinking is correct or not. Can someone please verify? Thanks in advance.
$RPM_BUILD_ROOT (or the equivalent %{buildroot} SPEC file macro) always holds the directory under which RPM will look for any files to package. The RPM scripts (e.g. the script that compresses the manual pages) will also use that value to know where to look for the files that were just installed. Normally, this value will be non-empty and contain a location away from the system directories - usually somewhere under /tmp or /var/tmp.
The author of the SPEC file is expected to make sure that make install (or whatever installer the software in question is using) will place any files under $RPM_BUILD_ROOT, with the same hierarchy that should be used when the software is finally installed. E.g. to have RPM install ls in /bin/ls, the %install SPEC file section should make sure that ls is placed in $RPM_BUILD_ROOT/bin/ls.
The author of the SPEC file is also expected to use the BuildRoot: tag to specify a proper location. Alternatively, the build system could have an rpmrc RPM configuration file with a proper entry. In any case the build root should be set, so that:
Normal users will be able to build the source package.
Should the superuser ever build the source package, the build process will not clobber any system files, unless the superuser installs the resulting binary package. And yes, there may be a good reason to build some packages as root - for example, running the full glibc testsuite requires root privileges for some tests.
That said, RPM can and will build a package with an empty build root variable. In that case both the build install and the final destination locations will coincide. A potential call to e.g. make install will use the default locations, thus clobbering the system files under e.g. /usr/lib if run with sufficient privileges. Additionally, having /usr/bin/* in your %files section will happily pull the whole contents of the build host /usr/bin/ directory into your binary package.
Bottom line:
Never use an empty build root.
Do not build packages as root unless there is absolutely no other way.
the file ~/.rpmmacros defines the paths per user:
%_topdir %(echo $HOME)/rpmbuild
%_tmppath %{_topdir}/tmp
and one can also define them with rpmbuild command line parameters:
rpmbuild --define '_topdir /home/username/rpmbuild'

Linux error while loading shared libraries: cannot open shared object file: No such file or directory

Program is part of the Xenomai test suite, cross-compiled from Linux PC into Linux+Xenomai ARM toolchain.
# echo $LD_LIBRARY_PATH
/lib
# ls /lib
ld-2.3.3.so libdl-2.3.3.so libpthread-0.10.so
ld-linux.so.2 libdl.so.2 libpthread.so.0
libc-2.3.3.so libgcc_s.so libpthread_rt.so
libc.so.6 libgcc_s.so.1 libstdc++.so.6
libcrypt-2.3.3.so libm-2.3.3.so libstdc++.so.6.0.9
libcrypt.so.1 libm.so.6
# ./clocktest
./clocktest: error while loading shared libraries: libpthread_rt.so.1: cannot open shared object file: No such file or directory
Is the .1 at the end part of the filename? What does that mean anyway?
Your library is a dynamic library.
You need to tell the operating system where it can locate it at runtime.
To do so,
we will need to do those easy steps:
Find where the library is placed if you don't know it.
sudo find / -name the_name_of_the_file.so
Check for the existence of the dynamic library path environment variable(LD_LIBRARY_PATH)
echo $LD_LIBRARY_PATH
If there is nothing to be displayed, add a default path value (or not if you wish to)
LD_LIBRARY_PATH=/usr/local/lib
We add the desired path, export it and try the application.
Note that the path should be the directory where the path.so.something is. So if path.so.something is in /my_library/path.so.something, it should be:
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/my_library/
export LD_LIBRARY_PATH
./my_app
Reference to source
Here are a few solutions you can try:
ldconfig
As AbiusX pointed out: If you have just now installed the library, you may simply need to run ldconfig.
sudo ldconfig
ldconfig creates the necessary links and cache to the most recent
shared libraries found in the directories specified on the command
line, in the file /etc/ld.so.conf, and in the trusted directories
(/lib and /usr/lib).
Usually your package manager will take care of this when you install a new library, but not always, and it won't hurt to run ldconfig even if that is not your issue.
Dev package or wrong version
If that doesn't work, I would also check out Paul's suggestion and look for a "-dev" version of the library. Many libraries are split into dev and non-dev packages. You can use this command to look for it:
apt-cache search <libraryname>
This can also help if you simply have the wrong version of the library installed. Some libraries are published in different versions simultaneously, for example, Python.
Library location
If you are sure that the right package is installed, and ldconfig didn't find it, it may just be in a nonstandard directory. By default, ldconfig looks in /lib, /usr/lib, and directories listed in /etc/ld.so.conf and $LD_LIBRARY_PATH. If your library is somewhere else, you can either add the directory on its own line in /etc/ld.so.conf, append the library's path to $LD_LIBRARY_PATH, or move the library into /usr/lib. Then run ldconfig.
To find out where the library is, try this:
sudo find / -iname *libraryname*.so*
(Replace libraryname with the name of your library)
If you go the $LD_LIBRARY_PATH route, you'll want to put that into your ~/.bashrc file so it will run every time you log in:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path/to/library
Update
While what I write below is true as a general answer about shared libraries, I think the most frequent cause of these sorts of message is because you've installed a package, but not installed the -dev version of that package.
Well, it's not lying - there is no libpthread_rt.so.1 in that listing. You probably need to re-configure and re-build it so that it depends on the library you have, or install whatever provides libpthread_rt.so.1.
Generally, the numbers after the .so are version numbers, and you'll often find that they are symlinks to each other, so if you have version 1.1 of libfoo.so, you'll have a real file libfoo.so.1.0, and symlinks foo.so and foo.so.1 pointing to the libfoo.so.1.0. And if you install version 1.1 without removing the other one, you'll have a libfoo.so.1.1, and libfoo.so.1 and libfoo.so will now point to the new one, but any code that requires that exact version can use the libfoo.so.1.0 file. Code that just relies on the version 1 API, but doesn't care if it's 1.0 or 1.1 will specify libfoo.so.1. As orip pointed out in the comments, this is explained well at here.
In your case, you might get away with symlinking libpthread_rt.so.1 to libpthread_rt.so. No guarantees that it won't break your code and eat your TV dinners, though.
You need to ensure that you specify the library path during
linking when you compile your .c file:
gcc -I/usr/local/include xxx.c -o xxx -L/usr/local/lib -Wl,-R/usr/local/lib
The -Wl,-R part tells the resulting binary to also look for the library
in /usr/local/lib at runtime before trying to use the one in /usr/lib/.
Try adding LD_LIBRARY_PATH, which indicates search paths, to your ~/.bashrc file
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path_to_your_library
It works!
The linux.org reference page explains the mechanics, but doesn't explain any of the motivation behind it :-(
For that, see Sun Linker and Libraries Guide
In addition, note that "external versioning" is largely obsolete on Linux, because symbol versioning (a GNU extension) allows you to have multiple incompatible versions of the same function to be present in a single library. This extension allowed glibc to have the same external version: libc.so.6 for the last 10 years.
cd /home/<user_name>/
sudo vi .bash_profile
add these lines at the end
LD_LIBRARY_PATH=/usr/local/lib:<any other paths you want>
export LD_LIBRARY_PATH
Another possible solution depending on your situation.
If you know that libpthread_rt.so.1 is the same as libpthread_rt.so then you can create a symlink by:
ln -s /lib/libpthread_rt.so /lib/libpthread_rt.so.1
Then ls -l /lib should now show the symlink and what it points to.
I had a similar error and it didn't fix with giving LD_LIBRARY_PATH in ~/.bashrc .
What solved my issue is by adding .conf file and loading it.
Go to terminal an be in su.
gedit /etc/ld.so.conf.d/myapp.conf
Add your library path in this file and save.(eg: /usr/local/lib).
You must run the following command to activate path:
ldconfig
Verify Your New Library Path:
ldconfig -v | less
If this shows your library files, then you are good to go.
running:
sudo ldconfig
was enough to fix my issue.
I had this error when running my application with Eclipse CDT on Linux x86.
To fix this:
In Eclipse:
Run as -> Run configurations -> Environment
Set the path
LD_LIBRARY_PATH=/my_lib_directory_path
Wanted to add, if your libraries are in a non standard path, run ldconfig followed by the path.
For instance I had to run:
sudo ldconfig /opt/intel/oneapi/mkl/2021.2.0/lib/intel64
to make R compile against Intel MKL
All I had to do was run:
sudo apt-get install libfontconfig1
I was in the folder located at /usr/lib/x86_64-linux-gnu and it worked perfectly.
Try to install lib32z1:
sudo apt-get install lib32z1
If you are running your application on Microsoft Windows, the path to dynamic libraries (.dll) need to be defined in the PATH environment variable.
If you are running your application on UNIX, the path to your dynamic libraries (.so) need to be defined in the LD_LIBRARY_PATH environment variable.
The error occurs as the system cannot refer to the library file mentioned. Take the following steps:
Running locate libpthread_rt.so.1 will list the path of all the files with that name. Let's suppose a path is /home/user/loc.
Copy the path and run cd home/USERNAME. Replace USERNAME with the name of the current active user with which you want to run the file.
Run vi .bash_profile and at the end of the LD_LIBRARY_PATH parameter, just before ., add the line /lib://home/usr/loc:.. Save the file.
Close terminal and restart the application. It should run.
I got this error and I think its the same reason of yours
error while loading shared libraries: libnw.so: cannot open shared
object file: No such file or directory
Try this. Fix permissions on files:
cd /opt/Popcorn (or wherever it is)
chmod -R 555 * (755 if not ok)
I use Ubuntu 18.04
Installing the corresponding -dev package worked for me,
sudo apt install libgconf2-dev
Before installing the above package, I was getting the below error:
turtl: error while loading shared libraries: libgconf-2.so.4: cannot open shared object file: No such file or directory
I got this error and I think its the same reason of yours
error while loading shared libraries: libnw.so: cannot open shared object
file: No such file or directory
Try this. Fix permissions on files:
sudo su
cd /opt/Popcorn (or wherever it is)
chmod -R 555 * (755 if not ok)
chown -R root:root *
A similar problem can be found here.
I've tried the mentioned solution and it actually works.
The solutions in the previous questions may work. But the following is an easy way to fix it.
It works by reinstalling the package libwbclient
in fedora:
dnf reinstall libwbclient
You can read about libraries here:
https://domiyanyue.medium.com/c-development-tutorial-4-static-and-dynamic-libraries-7b537656163e

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