Erlang port driver example

 · gcc -o exampledrv -fpic -shared complex.c port_driver.c But the compiler was unable to find the header erl_driver.h, so I proceeded to compile with gcc -o exampledrv -fpic -shared complex.c port_driver.c -I/usr/local/lib/erlang/usr/include -L -lerl_driver which compiled without any errors; but I am unable to run compex5: start("./exampledrv"). ; because the . Returning Large Binaries without Copying from a Driver. To avoid copying data when a large binary is sent or returned from the driver to an Erlang process, the driver must first allocate the binary and then send it to an Erlang process in some way. Use driver_alloc_binary () to allocate a binary. There are several ways to send a binary. An Erlang driver is a library containing a set of native driver callback functions that the Erlang Virtual Machine calls when certain events occur. There can be multiple instances of a driver, each instance is associated with an Erlang port. Warning.

start() - start("example1_drv"). start(SharedLib) - case erl_ddll:load_driver(".", SharedLib) of ok - ok; {error, already_loaded} - ok; _ - exit({error, could_not_load_driver}) end, spawn(fun() - init(SharedLib) end). init(SharedLib) - register(example1_lid, self()), Port = open_port({spawn, SharedLib}, []), loop(Port). stop() - example1_lid! stop. twice(X) - call_port({twice, X}). sum(X,Y) - call_port({sum, X, Y}). call_port(Msg) - example1_lid! {call, self(), Msg}, receive. disconnect(Port) - R = binary_to_term(port_control(Port,?DRV_DISCONNECT, "")), port_close(Port), R. select(Port, Query) - binary_to_term(port_control(Port,?DRV_SELECT, Query)). The API is simple: connect/1 loads the driver, opens it, and logs on to the database, returning the Erlang port if successful. This section outlines an example of how to solve the example problem in Problem Example by using a linked-in port driver. A port driver is a linked-in driver that is accessible as a port from an Erlang program. It is a shared library (SO in UNIX, DLL in Windows), with special entry points. The Erlang runtime system calls these entry points when the driver is started and when data is sent to the port. The port driver can also send data to Erlang.

In Erlang, ports are used for communication between different programs. A socket is a communication endpoint that allows machines to communicate over the. Functions such as port_info/1 and port_info/2 are wrappers to provide more similar or more details than erlang:port_info/, and, for inet ports, statistics. C source code location and Erlang environment. The C source code should be located in the $(C_SRC_DIR) directory. It defaults to c_src/. Should.