Class DynLib

Dynamic Loader support.

class DynLib

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Summary

Dynamic Loader support.

This class allows to load functions from dynamic link library or shared objects.

Init Block

Dynamic Loader support.

init DynLib

This class allows to load functions from dynamic link library or shared objects.

Methods

get()

Gets a dynamic symbol in this library.

DynLib.get( decl, [deletor] )

On success, the returned DynFunction instance has all the needed informations to perform calls directed to the foreign library.

As the call method of DynFunction is performing the actual call, if the other informations are not needed, it is possible to get a callable symbol by accessing directly the call property:

   allocate = mylib.get( "struct THING* allocate()" )
   use = mylib.get( "void use( struct THING* data )" )
   dispose = mylib.get( "void dispose( struct THING* data )" )

   // create an item
   item = allocate()

   // use it
   use( item )

   // and free it
   dispose( item )

Note: The allocate, use and dispose items in this examples are DynFunction instances; they can be directly called as they offer a call__() override.

In cases like the one in this example, it is possible to associate an automatic deletor function directly in the first call:

   allocate = mylib.get( "struct THING* allocate()", "void dispose( struct THING* data )" )
   use = mylib.get( "void use( struct THING* data )" )

   // create an item
   item = allocate()

   // use it
   use( item )

   // ...

Doing so, the items returned via a function returning opaque data (struct pointers) are automatically deleted when the garbage collector is called.

See the main page of this document for more details on safety.

query()

Gets a dynamic symbol in this library.

DynLib.query( decl, [deletor] )

This function is equivalent to DynLib.get, except for the fact that it returns nil instead of raising an error if the given function is not found. Some program logic may prefer a raise when the desired function is not there (as it is supposed to be there), other may prefer just to peek at the library for optional content.

unload()

Unloads a dynamic library from memory.

DynLib.unload( )

Using any of the functions loaded from this library after this call may cause immediate crash of the host application.