/* * %CopyrightBegin% * * Copyright Ericsson AB 1996-2016. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * %CopyrightEnd% */ /* Purpose: Multidriver interface This is an example of a driver which allows multiple instances of itself. I.e have one erlang process execute open_port(multi......) and at the same time have another erlang process open another port running multi there as well. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include "erl_driver.h" #include "sys.h" #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #define MAXCHANNEL 20 static char buf[BUFSIZ]; static ErlDrvData multi_start(ErlDrvPort, char*); static int multi_init(void); static void multi_stop(ErlDrvData),multi_erlang_read(ErlDrvData, char*, int); struct driver_entry multi_driver_entry = { multi_init, multi_start, multi_stop, multi_erlang_read, NULL, NULL, "multi" }; struct channel { ErlDrvPort portno; int channel; }; struct channel channels[MAXCHANNEL]; /* Max MAXCHANNEL instances */ static int multi_init(void) { memzero(channels,MAXCHANNEL * sizeof(struct channel)); return 0; } static ErlDrvData multi_start(ErlDrvPort port, char* buf) { int chan; chan = get_new_channel(); channels[port].portno = port; channels[port].channel = chan; fprintf(stderr,"Opening channel %d port is %d\n",chan,port); return (ErlDrvData)port; } static int multi_stop(ErlDrvData port) { fprintf(stderr,"Closing channel %d\n",channels[port].channel); remove_channel(channels[(int)port].channel); } static int multi_erlang_read(ErlDrvData port, char* buf, int count) { fprintf(stderr,"Writing %d bytes to channel %d\n", count, channels[(int)port].channel); } /* These two funs are fake */ int get_new_channel() { static int ch = 1; return(ch++); } void remove_channel(int ch) { }