Erlang: The specified module was not found
I have a minimal Erlang port driver:
erl_driver_bridge.c → erl_driver_bridge.dll
#define __WIN32__
#include "erl_driver.h"
typedef struct {
ErlDrvPort port;
} erl_driver_bridge_data;
static ErlDrvData bridge_start(ErlDrvPort port, char *buff) {
erl_driver_bridge_data* d =
(erl_driver_bridge_data*)driver_alloc(sizeof(erl_driver_bridge_data));
d->port = port;
return (ErlDrvData)d;
}
static void bridge_stop(ErlDrvData data) {
driver_free((char*)data);
}
static void bridge_output(ErlDrvData data, char *buff, int bufflen) {
erl_driver_bridge_data* d = (erl_driver_bridge_data*)data;
}
ErlDrvEntry erl_driver_bridge_entry = {
NULL, /* F_PTR init, N/A */
bridge_start, /* L_PTR start, called when port is opened */
bridge_stop, /* F_PTR stop, called when port is closed */
bridge_output, /* F_PTR output, called when erlang has sent */
NULL, /* F_PTR ready_input */
NULL, /* F_PTR ready_output */
"erl_driver_bridge", /* char *driver_name, the argument to open_port */
NULL, /* F_PTR finish, called when unloaded */
NULL, /* Not used */
NULL, /* F_PTR control, port_command callback */
NULL, /* F_PTR timeout, reserved */
NULL, /* F_PTR outputv, reserved */
NULL, /* F_PTR ready_async */
NULL, /* F_PTR flush */
NULL, /* F_PTR call */
NULL, /* F_PTR event */
ERL_DRV_EXTENDED_MARKER,
ERL_DRV_EXTENDED_MAJOR_VERSION,
ERL_DRV_EXTENDED_MINOR_VERSION,
0,
NULL, /* Reserved -- Used by emulator internally */
NULL, /* F_PTR process_exit */
};
DRIVER_INIT(erl_driver_bridge) {
return &erl_driver_bridge_entry;
}
Then I try to load it into Erlang:
case erl_ddll:load_driver(".", erl_driver_bridge) of
ok -> ok;
{error, Error} -> erl_ddll:format_error(Error)
end.
What produces:
The specified module was not found.
I have verified that the driver exists in the current directory and even the full path is specified, but Erlang still doesn't see it. Any ideas?
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3 answers
You should probably use "file: get_cwd" to get the current working directory first and add the next path.
Also handy, but probably unrelated to your current question: have you checked the path of the code that the Erlang emulator uses? Use the 'code: get_path' function ( http://www.erlang.org/doc/man/code.html ) to check the search path. You can use "code: add_path" to conveniently insert paths.
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