void*
     dlopen(const char* path, int mode);

DESCRIPTION

     dlopen() examines the mach-o file specified by path.  If the file is com-
     patible with the current process and has not already been loaded into the
     current process, it is loaded and linked.  After being linked, if it con-
     tains any initializer functions, they are called, before dlopen()
     returns.  dlopen() can load dynamic libraries and bundles.  It returns a
     handle that can be used with dlsym() and dlclose().  A second call to
     dlopen() with the same path will return the same handle, but the internal
     reference count for the handle will be incremented.  Therefore all
     dlopen() calls should be balanced with a dlclose() call.

     If a null pointer is passed in path, dlopen() returns a handle equivalent
     to RTLD_DEFAULT.

     mode contains options to dlopen().  It must contain one or more of the
     following values, possibly ORed together:

     RTLD_LAZY   Each external function reference is bound the first time the
                 function is called.

     RTLD_NOW    All external function references are bound immediately during
                 the call to dlopen().

     RTLD_LAZY is normally preferred, for reasons of efficiency.  However,
     RTLD_NOW is useful to ensure that any undefined symbols are discovered
     during the call to dlopen().  If neither RTLD_LAZY nor RTLD_NOW is speci-
     fied, the default is RTLD_LAZY.

     One of the following flags may be ORed into the mode argument:

     RTLD_GLOBAL   Symbols exported from this image (dynamic library or bun-
                   dle) will be available to any images build with
                   -flat_namespace option to ld(1) or to calls to dlsym() when
                   using a special handle.

     RTLD_LOCAL    Symbols exported from this image (dynamic library or bun-
                   dle) are generally hidden and only availble to dlsym() when
                   directly using the handle returned by this call to
                   dlopen().  If neither RTLD_GLOBAL nor RTLD_LOCAL is speci-
                   fied, the default is RTLD_GLOBAL.

SEARCHING

     dlopen() uses a series of steps to find a compatible mach-o file.  The
     first compatible file found is used.

     1) If the directory specified by path does not contain a slash '/' (i.e.
     it is a leaf name) then the environment variable LD_LIBRARY_PATH is used.
     LD_LIBRARY_PATH should be a colon seperated list of directories.
     Note: There are no configuration files to control dlopen searching.

     Note: Mac OS X uses "fat" files to combine 32-bit and 64-bit libraries.
     This means there are no separate 32-bit and 64-bit search paths.

RETURN VALUES

     If dlopen() fails, it returns a null pointer, and sets an error condition
     which may be interrogated with dlerror().

AUTHORS

     Mac OS X 10.3 incorporated the dlcompat package written by Jorge Acereda
     <jacereda@users.sourceforge.net> and Peter O'Gorman <ogor-
     man@users.sourceforge.net>.

     In Mac OS X 10.4, dlopen was rewritten to be a native part of dyld.

SEE ALSO

     dlclose(3) dlsym(3) dlerror(3) dyld(3) ld(1)

BSD                            February 8, 2005                            BSD