library.dynam {base}R Documentation

Loading Shared Libraries


Load the specified file of compiled code if it has not been loaded already, or unloads it.


library.dynam(chname, package = NULL, lib.loc = NULL,
              verbose = getOption("verbose"),
              file.ext = .Platform$dynlib.ext, ...)

library.dynam.unload(chname, libpath,
              verbose = getOption("verbose"),
              file.ext = .Platform$dynlib.ext)



chname a character string naming a shared library to load.
package a character vector with the names of packages to search through, or NULL. By default, all packages in the search path are used.
lib.loc a character vector describing the location of R library trees to search through, or NULL. The default value of NULL corresponds to all libraries currently known.
libpath the path to the loaded package whose shared library is to be unloaded.
verbose a logical value indicating whether an announcement is printed on the console before loading the shared library. The default value is taken from the verbose entry in the system options.
file.ext the extension to append to the file name to specify the library to be loaded. This defaults to the appropriate value for the operating system.
... additional arguments needed by some libraries that are passed to the call to dyn.load to control how the library is loaded.
new a list of "DLLInfo" objects corresponding to the shared libraries loaded by packages. Can be missing.


library.dynam is designed to be used inside a package rather than at the command line, and should really only be used inside .First.lib or .onLoad. The system-specific extension for shared libraries (e.g., ‘.so’ or ‘.sl’ on Unix systems) should not be added. Note that to allow for versioned installs, the chname argument should not be set to the pkgname argument of .First.lib or .onLoad.

library.dynam.unload is designed for use in .Last.lib or .onUnload: it unloads the shared object and updates the value of .dynLibs()

.dynLibs is used for getting (with no argument) or setting the shared libraries which are currently loaded by packages (using library.dynam).


If chname is not specified, library.dynam returns an object of class "DLLInfoList" corresponding to the shared libraries loaded by packages.
If chname is specified, an object of class "DLLInfo" that identifies the DLL and can be used in future calls is returned invisibly. For packages that have name spaces, a list of these objects is stored in the name space's environment for use at run-time.
Note that the class DLLInfo has an overloaded method for $ which can be used to resolve native symbols within that DLL.
library.dynam.unload invisibly returns an object of class "DLLInfo" identifying the DLL successfully unloaded.
.dynLibs returns an object of class "DLLInfoList" corresponding corresponding to its current value.


Do not use dyn.unload on a shared object loaded by library.dynam: use library.dynam.unload to ensure that .dynLibs gets updated. Otherwise a subsequent call to library.dynam will be told the object is already loaded.


Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

getLoadedDLLs for information on "DLLInfo" and "DLLInfoList" objects.

.First.lib, library, dyn.load, .packages, .libPaths

SHLIB for how to create suitable shared libraries.


## Which DLLs were "dynamically loaded" by packages?

[Package base version 2.5.0 Index]