Dynamic Linker¶
dlopen
(libfile::AbstractString[, flags::Integer])¶Load a shared library, returning an opaque handle.
The optional flags argument is a bitwise-or of zero or more of
RTLD_LOCAL
,RTLD_GLOBAL
,RTLD_LAZY
,RTLD_NOW
,RTLD_NODELETE
,RTLD_NOLOAD
,RTLD_DEEPBIND
, andRTLD_FIRST
. These are converted to the corresponding flags of the POSIX (and/or GNU libc and/or MacOS) dlopen command, if possible, or are ignored if the specified functionality is not available on the current platform. The default flags are platform specific. On MacOS the defaultdlopen
flags areRTLD_LAZY|RTLD_DEEPBIND|RTLD_GLOBAL
while on other platforms the defaults areRTLD_LAZY|RTLD_DEEPBIND|RTLD_LOCAL
. An important usage of these flags is to specify non default behavior for when the dynamic library loader binds library references to exported symbols and if the bound references are put into process local or global scope. For instanceRTLD_LAZY|RTLD_DEEPBIND|RTLD_GLOBAL
allows the library’s symbols to be available for usage in other shared libraries, addressing situations where there are dependencies between shared libraries.
dlopen_e
(libfile::AbstractString[, flags::Integer])¶Similar to
dlopen()
, except returns aNULL
pointer instead of raising errors.
dlsym
(handle, sym)¶Look up a symbol from a shared library handle, return callable function pointer on success.
dlsym_e
(handle, sym)¶Look up a symbol from a shared library handle, silently return
NULL
pointer on lookup failure.
dlclose
(handle)¶Close shared library referenced by handle.
dlext
¶File extension for dynamic libraries (e.g. dll, dylib, so) on the current platform.
find_library
(names, locations)¶Searches for the first library in
names
in the paths in thelocations
list,DL_LOAD_PATH
, or system library paths (in that order) which can successfully be dlopen’d. On success, the return value will be one of the names (potentially prefixed by one of the paths in locations). This string can be assigned to aglobalconst
and used as the library name in futureccall
‘s. On failure, it returns the empty string.
DL_LOAD_PATH
¶When calling
dlopen
, the paths in this list will be searched first, in order, before searching the system locations for a valid library handle.