The external package is to be considered as a black box. We will build a shared library and try linking it with the executable. Other linkers solaris comes to mind only accept it as two arguments. The same applies to wl,rpath flags if you need to use it instead. Why does ld need rpathlink when linking an executable. Scons is an open source software construction toolthat is, a nextgeneration build tool. Library paths in this definition are added to the executable at link time so that the added paths will be preferentially searched at runtime. The current state of affairs is well summarized on the debian wiki, which lists the library search path. So if test program has undefined reference error some variable or function not found in test itself and neither in libb. Frustratingly for me, i seem to keep ending up in a fight with the various developers cmake config files over what rpath should be set, among other things.
Dynamic linking loaders use the rpath to find required libraries. Why does ld need rpathlink when linking an executable against a. It acted as a modeldriven and versioncontrolled repository and software distribution hub. Original and default rpath list has higher precedence.
Gnu ld will accept it as either two arguments or a single argument with an as you suggest, so either can work. Unfortunately, software developers who have nondefault library search paths often forget to supply the wl,rpath or r options in their makefiles, with the result that the code. The difference between rpath and rpathlink is that directories specified by rpath options are included in the executable and used at runtime, whereas the rpathlink option is only effective at link time. Conary is designed, based on many years of linux software packaging and distribution development experience, to automate many of the tasks that have made it difficult to build linux distributions. Both rpath and runpath are used to specify directories to search for shared librariesdynamic. Think of scons as an improved, crossplatform substitute for the classic make utility with integrated functionality similar to autoconfautomake and compiler caches such as ccache. The bad old days before separate runtime vs linktime paths. Searching rpath in this way is only supported by native linkers and cross linkers which have been configured with the withsysroot option. Fixing rpathlink issues with crosscompilers sysprogs. Nov 10, 2010 were excited to announce rpath on windows. All upstream maintainers prefer runpath, and rpath has been deprecated for ten years.
I guess you need to know when to use rpath option and rpath link option. I havent used it for quite a while, but i think youd add something line rpathlink relative path to libz just before libpng14 is specified. Fixing rpathlink issues with crosscompilers september 26, 20 ivan shcherbakov if you are using a crosscompiler to build a nontrivial linux app e. Nowadays you specify the runtime path for an executable at link stage with the r or sometimes rpath flag to ld. Wl,rpathlink for secondary dependencies causes linking failure. In short, scons is an easier, more reliable and faster way to build software.
On an elf system, if the rpath and rpathlink options were not used, search the contents of. I guess you need to know when to use rpath option and rpathlink option. In computing, rpath designates the runtime search path hardcoded in an executable file or library. The rpath, or runpath if it is present, is where the runtime linker should look for the libraries needed for a program. Net deployment solution for windows, and finally gives operations the tool they need to keep up with the flood of apps and updates from development. My own general approach is to link executables with the rpath option, while they are in build tree and depend on other libraries in the build tree, to facilitate debugging, but upon installation make install, building packages to relink withoutrpath option and leave the task of finding the shared libraries to the appropriate dynamic linker configuration e. A semicolonseparated list specifying the rpath to use in installed targets for platforms that support it. With gnu autoconf, the normal condition is that prefix is the root of the file tree into which you install software locally, so the above. If you later link a program against this filter object, then, when you run the. Conary is meant to replace package managers like rpm and dpkg. To build rpath, you will need a version of solaris nevada newer than build 61, or a recent version of opensolaris.
Although i personally have no opinion on rpath vs runpath, these are facts. The difference between rpath and rpath link is that directories specified by rpath options are included in the executable and used at runtime, whereas the rpath link option is only effective at link time. Dec 02, 2005 with gnu autoconf, the normal condition is that prefix is the root of the file tree into which you install software locally, so the above command is fairly typical. To solve this issue, runpath first and rpath now is used. The latter is more convenient and means that rpaths are less likely to get in your way, since you can override them. The rpath option is also used when locating shared objects which are needed by shared objects explicitly included in the link. The rpathlink option will let you specify the path for secondorder dependencies in a way that doesnt hardcode them in.
When using dynamic linking shared libraries, the operating system. As we approach the end of our beta testing, we would like to encourage the most extensive testing you are willing to do. As such, you have to use wl, or xlinker to get it only to the linker. The difference between rpath and rpathlink is that directories specified by rpath options are included in the executable and used at runtime, whereas the. The why and how of rpath flameeyes english, technical 20100620 this post is brought to you by a conversation with fabio, which actually reminded me of an older conversation i had with someone else exactly whom, right now, escapes me about the ability to inject rpath values into alreadybuilt binaries. To instruct easybuild to enable rpath linking, use the rpath configuration. I install intel parallel studio xe cluster edition 16 under ubuntu 14. There is an equivalent in windows in the form of qlocation,link switch. Today, both ubuntu and arch compilers use runpath by default, and of course the android linker has no rpath support.
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