A graphical program execution environment that facilitates communication between a producer program and a consumer program is disclosed. The producer program may store data in a memory block allocated by the producer program. A graphical program may communicate with the producer program to obtain a reference to the memory block. The graphical program may asynchronously pass the reference to the consumer program, e.g., may pass the reference without blocking or waiting while the consumer program accesses the data in the memory block. After the consumer program is finished accessing the data, the consumer program may asynchronously notify the graphical program execution environment to release the memory block. The graphical program execution environment may then notify the producer program that the block of memory is no longer in use so that the producer program can de-allocate or re-use the memory block.