|DLCLOSE(3P)||POSIX Programmer's Manual||DLCLOSE(3P)|
int dlclose(void *handle);
An application writer may use dlclose() to make a statement of intent on the part of the process, but this statement does not create any requirement upon the implementation. When the symbol table handle is closed, the implementation may unload the executable object files that were loaded by dlopen() when the symbol table handle was opened and those that were loaded by dlsym() when using the symbol table handle identified by handle.
Once a symbol table handle has been closed, an application should assume that any symbols (function identifiers and data object identifiers) made visible using handle, are no longer available to the process.
Although a dlclose() operation is not required to remove any functions or data objects from the address space, neither is an implementation prohibited from doing so. The only restriction on such a removal is that no function nor data object shall be removed to which references have been relocated, until or unless all such references are removed. For instance, an executable object file that had been loaded with a dlopen() operation specifying the RTLD_GLOBAL flag might provide a target for dynamic relocations performed in the processing of other relocatable objects—in such environments, an application may assume that no relocation, once made, shall be undone or remade unless the executable object file containing the relocated object has itself been removed.
The following sections are informative.
#include <dlfcn.h> int eret; void *mylib; ... /* Open a dynamic library and then close it ... */ mylib = dlopen("mylib.so", RTLD_LOCAL | RTLD_LAZY); ... eret = dlclose(mylib); ...
Implementations are also free to re-use a handle. For these reasons, the value of a handle must be treated as an opaque data type by the application, used only in calls to dlsym() and dlclose().
The Base Definitions volume of POSIX.1‐2008, <dlfcn.h>
Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .
|2013||IEEE/The Open Group|