I've tried repeatedly installing jzmq on Mac OS X. Whatever I do, I hit a brick wall with this exception: java.lang.UnsatisfiedLinkError: no jzmq in java.library.path I have successfully installed (pkg-config and) libzmq and libjzmq into. Changing the Default Library in Rstudio to a Different Default Library (Temporary) We offer private, customized training for 3 or more people at your site or online. Many users have R installed in a personal workspace, but want to install packages into a common area so that their entire team can use them and preserve version consistency.
(Redirected from Rpath (linking))
In computing, rpath designates the run-timesearch path hard-coded in an executable file or library. Dynamic linkingloaders use the rpath to find required libraries.
Specifically, it encodes a path to shared libraries into the header of an executable (or another shared library). This RPATH header value (so named in the Executable and Linkable Format header standards) may either override or supplement the system default dynamic linking search paths.
The rpath of an executable or shared library is an optional entry in the
.dynamic
section of the ELF executable or shared libraries, with the type DT_RPATH
, called the DT_RPATH
attribute. It can be stored there at link time by the linker. Tools such as chrpath
and patchelf
can create or modify the entry later.Use of the DT_RPATH entry by the dynamic linker[edit]
The different dynamic linkers for ELF implement the use of the
DT_RPATH
attribute in different ways.GNU ld.so[edit]
The dynamic linker of the GNU C Library searches for shared libraries in the following locations:[1]
- The (colon-separated) paths in the
DT_RPATH
dynamic section attribute of the binary if present and theDT_RUNPATH
attribute does not exist. - The (colon-separated) paths in the environment variable
LD_LIBRARY_PATH
, unless the executable is asetuid/setgid
binary, in which case it is ignored.LD_LIBRARY_PATH
can be overridden by calling the dynamic linker with the option--library-path
(e.g./lib/ld-linux.so.2 --library-path $HOME/mylibs myprogram
). - The (colon-separated) paths in the
DT_RUNPATH
dynamic section attribute of the binary if present. - Lookup based on the
ldconfig
cache file (often located at/etc/ld.so.cache
) which contains a compiled list of candidate libraries previously found in the augmented library path (set by/etc/ld.so.conf
). If, however, the binary was linked with the-z nodefaultlib
linker option, libraries in the default library paths are skipped. - In the trusted default path
/lib
, and then/usr/lib
. If the binary was linked with the-z nodefaultlib
linker option, this step is skipped.
Notes:
- The option
--inhibit-rpath LIST
of the dynamic linker instructs it to ignoreDT_RPATH
andDT_RUNPATH
attributes of the object names in LIST. - Libraries specified by the environment variable
LD_PRELOAD
and then those listed in/etc/ld.so.preload
are loaded before the search begins. A preload can thus be used to replace some (or all) of the requested library's normal functionalities, or it can simply be used to supply a library that would otherwise not be found. - Static libraries are searched and linked into the ELF file at link time and are not searched at run time.
The role of GNU ld[edit]
The GNU Linker (GNU ld) implements a feature which it calls 'new-dtags', which can be used to insert an rpath that has lower precedence than the
LD_LIBRARY_PATH
environment variable.[2]If the new-dtags feature is enabled in the linker (
--enable-new-dtags
), GNU ld
, besides setting the DT_RPATH
attribute, also sets the DT_RUNPATH
attribute to the same string. At run time, if the dynamic linker finds a DT_RUNPATH
attribute, it ignores the value of the DT_RPATH
attribute, with the effect that LD_LIBRARY_PATH
is checked first and the paths in the DT_RUNPATH
attribute are only searched afterwards.The ld dynamic linker does not search DT_RUNPATH locations for transitive dependencies, unlike DT_RPATH. [3]
Instead of specifying the
-rpath
to the linker, the environment variable LD_RUN_PATH
can be set to the same effect.Solaris ld.so[edit]
The dynamic linker of Solaris, specifically
/lib/ld.so
of SunOS 5.8 and similar systems looks for libraries in the directories specified in the LD_LIBRARY_PATH variable before looking at the DT_RPATH
attribute. Sun Microsystems was the first[citation needed] to introduce dynamic library loading. Sun later added the rpath option to ld and used it in essential libraries as an added security feature. GNU ld did the same to support Sun-style dynamic libraries.Example[edit]
In this example, GNU or Sun ld (ld.so) will REFUSE to load termcap for a program needing it unless the file termcap.so is in /lib/ and named termcap.so.4. LD_LIBRARY_PATH is ignored. If /lib/termcap.so.4 is removed to remediate, the shell dies (one cannot load an alternate termcap.so and a rescue disk is needed, but also if a new termcap.so.4 has RPATH /lib, ld.so will refuse to use to load it unless it clobbered /lib/termcap.so.4). But there's another issue: it isn't safe to copy over some libs in /lib as they are 'in use,' further restricting the would-be lib tester. Furthermore, SONAME termcap.so.4 vs. SONAME termcap.so means programs needing basic termcap.so are denied because the library above deleted the ABI access to basic support.
Old Linux/Sun used the above, which allows a user to direct any program to use any termcap.so they specify in LD_LIBRARY_PATH, or what is found in /usr/local/lib(n) using the search rules such as ld.so.conf. However, GNU ld always uses /lib or /usr/lib regardless before LD_LIBRARY_PATH, so first /lib/termcap.so is moved to /usr/local/lib and that mentioned in ld.so.conf, which enables use of moving libs and ld.so.conf or use of LD_LIBRARY_PATH to use. A preferred practice is to use 'SONAME termcap.so' and have programs check version (all libs do support that) to use features available, but that was often skipped in old releases due to slow computing speed and lack of time to code correctly.
Jan 12, 2020 Apple hides the Library folder by setting a file system flag associated with the folder. You can toggle the visibility flag for any folder on your Mac; Apple just chose to set the Library folder's visibility flag to the off state by default. The Library Folder on your Mac contains Preference Files, Caches, and Application Support Data. While regular Mac users may not find the need to access the Hidden Library Folder, advanced Mac users will at times come across the need to access files inside the Library Folder for. What is hd library mac. Some troubleshooting procedures require you to navigate to and view a hidden folder on Mac. You can access the Library folder with the Go To Folder command or from the Terminal app. Access the Library folder in Finder: In Finder, choose Go Go To Folder In the Go To The Folder field, enter /library/ Click Go. Access the Library folder directly through the Terminal: Click the Spotlight Search.
That being said, test this kind of thing thoroughly on a given platform before deciding to rely on it. Release administrators today are not guaranteed to respect past guidelines or documentation. Some UNIX varieties link and load in a completely different way. rpath is specific to ld shipped with a particular distribution.
Lastly, as said, rpath is a security feature however 'mandatory access control' (MAC) and other techniques can be as effective or more effective than rpath to control lib reading and writing.
Control over rpath using today's compilers is often nearly impossible given lengthy and convoluted make(1) scripting. Worse, some build scripts ignore --disable-rpath even though they present it as an option. It would be time-consuming and frustrating, and probably unfeasible, to fix build scripting in every odd program to compile.
A simple sh(1) 'wrapper' can call the real ld, named ld.bin. The wrapper can filter in/out -rpath option before invoking ld.
However, note that some builds incorrectly use rpath instead of rpath-link or LD_LIBRARY_PATH or $(TOP)/dir/foo.so to locate intermediate products that stay in the build directory - thus backwardly demand rpath in the final product, which is a new issue concerning 'what is rpath'.
References[edit]
- ^'Linux / Unix Command: ld.so'. man7.org. Retrieved 19 February 2018.
- ^'Shared Libraries: distribution and build-system issues'. Official website of the Haskell Compiler. Retrieved 4 April 2019.
- ^https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/1253638
External links[edit]
- chrpath - a tool to change the
DT_RPATH
attribute of an executable and convert it to anDT_RUNPATH
attribute - FreeBSD devel/chrpath Port - Tool to modify DT_RPATH in existing ELF binaries
- patchELF - a small utility to modify the dynamic linker and
DT_RUNPATH
attribute of ELF executables.
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Rpath&oldid=942454129'
Posted on October 12, 2019 by Paul
In this tutorial, I will show you how to compile from source and install the current stable version of GCC on your macOS computer. The instructions from this tutorial were tested on Catalina (macOS 10.15).
Clang, the default compiler for macOS, supports only C, C++, Objective-C and Objective-C++. If you are interested in a modern Fortran compiler, e.g. you will need gfortran that comes with GCC. Another reason to have the latest stable version of GCC on your macOS is that it provides you with an alternative C and C++ compiler. Testing your code with two different compilers is always a good idea.
Building GCC 9 from sources could take some time, in my case it took about two hours on a MacBook Air with a 16GB of RAM.
In order to compile GCC from sources you will need a working C++ compiler. In the remaining of this article I will assume that you have installed the Command Line Tools for Xcode. At the time of this writing Apple’s Command Line Tools maps the gcc and g++ to clang and clang++. If you don’t have the Command Line Tools installed, open a Terminal and write:
which will guide you through the installation process.
Let’s start by creating a working folder:
Next, we can download and extract the latest stable version of GCC:
GCC 9 depends on a couple of other libraries (GSL, GMP, MPFR and ISL) that can be downloaded with:
the above four prerequisites will be built during the GCC build.
GCC expects to find the system headers in /usr/include which was removed starting with macOS Mojave. As a workaround, let’s create a folder with symbolic links to the system headers and libraries:
Please note that in the above, the last line does a deep copy of the include folder, we do a copy because we need to modify one of the header file in order to be able to build GCC. On a typical GNU/Linux system a more elegant solution would be to use fixinclude from GCC and the auotgen utility instead of manually modifying one of the system header files.
Next, we need to edit the file /usr/local/gcc_system_root/usr/include/Availability.h, at about line 300, just before:
e.g.:
find line 300 and paste the next snippet:
This is how the file looks around line 300 before the change:
This is how the file looks around line 300 after the change:
We are ready to compile GCC now. Be prepared that this could take some time … Since I’m interested only in the C, C++ and Fortran compilers, this is the configure command I’ve used on my machine:
The above command instructs the configure app to add a prefix to all the resulting executable programs, so for example if you want to invoke GCC 9.2.0 you will write gcc-9.2, the gcc command will invoke Apple’s version of clang.
If you are interested in building more compilers available in the GCC collection modify the –enable-languages configure option.
And now, the final touches:
Grab a coffee, maybe a book, and wait … this should take approximately, depending on your computer configuration, an hour … or more … and about 4.15GB of your disk space for the build folder.
Install the compiled gcc in /usr/local/gcc-9.2:
Now, you can keep the new compiler completely isolated from your Apple’s gcc compiler and, when you need to use it, just modify your path by writing in Terminal:
If you want to avoid writing the above command each time you open a Terminal, save the above command in the file .zshrc from your Home folder, e.g:
You should be able to invoke any of the newly compiled compilers C, C++, Fortran …, invoking g++ is as simple as writing in your Terminal:
Remember to erase the working folder from your HOME if you want to recover some space:
Greenfield Community College Library
Next, I’ll show you how to check if the compiler was properly installed by compiling and running a few examples. GCC 9 uses by default the C++14 standard and C11 for the C coders, you should be able to compile any valid C++14 code directly. In your favorite text editor, copy and save this test program (I’ll assume you will save the file in your Home directory):
Compiling and running the above lambda example:
We could also compile a C++ code that uses threads:
Next, we present a simple C++ code that uses regular expressions to check if the input read from stdin is a floating point number:
Gcc Add Library Path
If you are a Fortran programmer, you can use some of the Fortran 2008 features like doconcurrent with gfortran-9.2:
The above code can be compiled with (assuming you’ve saved it as tst_concurrent_do.f90):
If you are interested in learning more about the new C++11/C++14 syntax I would recommend reading The C++ Programming Language by Bjarne Stroustrup.
How to troubleshoot iTunes library & playlist importing. If doubleTwist does not present this dialog when your iTunes library is in an alternate location and your current iTunes playlists can not be imported, it may be that you have multiple copies of the iTunes XML file on your system. Please check your system for multiple copies of the. 2016-7-26 Sync your iTunes playlists, ratings, DRM-free video and more to your Android phone with doubleTwist Sync. Transfer your iTunes music library from your Windows PC to your Android device with doubleTwist Sync. DoubleTwist Sync supports free iTunes sync over USB and there's an optional premium upgrade for wireless synchronization using AirSync. 2019-2-19 Questions and bug reports about doubleTwist Sync for Mac and Windows. Show all All Planned Not planned Completed Answered No status Sort by newest post Newest post Recent activity Votes Comments. Doubletwist not loading library mac. If doubleTwist Sync on your Windows PC doesn't auto-detect your iTunes library or playlists, one of two things may be happening: The iTunes setting for sharing your music library info with other apps (iTunes Library XML) may be set to OFF by default. Your iTunes library is located in a non-standard location (such as a different hard drive).
Mac Gcc Library Path Map
or, Professional C++ by M. Gregoire, N. A. Solter, S. J. Kleper 2nd edition:
Gcc Library Database
If you need to brush your Fortran knowledge a good book is Modern Fortran Explained by M. Metcalf, J. Reid and M. Cohen:
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