programming erlang src code

/* example1_lid.c */ #include <stdio.h> #include "erl_driver.h" typedef struct { ErlDrvPort port; } example_data; static ErlDrvData example_drv_start(ErlDrvPort port, char *buff) { example_data* d = (example_data*)driver_alloc(sizeof(example_data)); d->port = port; return (ErlDrvData)d; } static void example_drv_stop(ErlDrvData handle) { driver_free((char*)handle); } static void example_drv_output(ErlDrvData handle, char *buff, int bufflen) { example_data* d = (example_data*)handle; char fn = buff[0], arg = buff[1], res; if (fn == 1) { res = twice(arg); } else if (fn == 2) { res = sum(buff[1], buff[2]); } driver_output(d->port, &res, 1); } ErlDrvEntry example_driver_entry = { NULL, /* F_PTR init, N/A */ example_drv_start, /* L_PTR start, called when port is opened */ example_drv_stop, /* F_PTR stop, called when port is closed */ example_drv_output, /* F_PTR output, called when erlang has sent data to the port */ NULL, /* F_PTR ready_input, called when input descriptor ready to read*/ NULL, /* F_PTR ready_output, called when output descriptor ready to write */ "example1_drv", /* char *driver_name, the argument to open_port */ NULL, /* F_PTR finish, called when unloaded */ NULL, /* F_PTR control, port_command callback */ NULL, /* F_PTR timeout, reserved */ NULL /* F_PTR outputv, reserved */ }; DRIVER_INIT(example_drv) /* must match name in driver_entry */ { return &example_driver_entry; }