问题
This was working fine last week. I would open
cd myprojectdir
erl
(erlang shell).
c(room).
{ok, R} = room:go().
then I could use gen_server to send messages to R, interacting with my room module.
I started in a cowboy routing branch. I was seeing things work fine, when I looked at it today I was getting compile errors. So I rolled back to my master branch. Still got errors in the shell, even rolling back a few commits, hm.
When I try to call room:go(), the other modules are printed as undef. If I compile each of them in turn, then room:go() will work.
room kicks off tables, tables kick off clocks, seats and game, game kicks off board and actions.
https://github.com/quantumproductions/tunnel
2> c(game).
{ok,game}
3> game:go().
** exception exit: undef
in function board:go/0
called as board:go()
in call from game:init/1 (game.erl, line 57)
in call from gen_server:init_it/6 (gen_server.erl, line 328)
in call from proc_lib:init_p_do_apply/3 (proc_lib.erl, line 247)
4> c(board).
{ok,board}
5> game:go().
** exception exit: undef
in function actions:go/0
called as actions:go()
in call from game:init/1 (game.erl, line 58)
in call from gen_server:init_it/6 (gen_server.erl, line 328)
in call from proc_lib:init_p_do_apply/3 (proc_lib.erl, line 247)
6> c(actions).
{ok,actions}
7> actions:go().
{ok,<0.93.0>}
8> game:go().
{ok,<0.95.0>}
9> c(room).
{ok,room}
10> room:go().
** exception exit: undef
in function table:go/0
called as table:go()
in call from room:tablePids/2 (room.erl, line 33)
in call from room:init/1 (room.erl, line 80)
in call from gen_server:init_it/6 (gen_server.erl, line 328)
in call from proc_lib:init_p_do_apply/3 (proc_lib.erl, line 247)
11> c(table).
{ok,table}
12> room:go().
** exception exit: undef
in function clock:go/0
called as clock:go()
in call from table:init/1 (table.erl, line 7)
in call from gen_server:init_it/6 (gen_server.erl, line 328)
in call from proc_lib:init_p_do_apply/3 (proc_lib.erl, line 247)
13> c(clock).
{ok,clock}
14> room:go().
** exception exit: undef
in function seats:go/0
called as seats:go()
in call from table:init/1 (table.erl, line 8)
in call from gen_server:init_it/6 (gen_server.erl, line 328)
in call from proc_lib:init_p_do_apply/3 (proc_lib.erl, line 247)
15> c(seats).
{ok,seats}
16> room:go().
** exception exit: undef
in function hall:go/0
called as hall:go()
in call from room:init/1 (room.erl, line 81)
in call from gen_server:init_it/6 (gen_server.erl, line 328)
in call from proc_lib:init_p_do_apply/3 (proc_lib.erl, line 247)
17> c(hall).
{ok,hall}
18> room:go().
{ok,<0.159.0>}
19>
=ERROR REPORT==== 29-Jan-2017::17:37:45 ===
Error in process <0.169.0> with exit value:
{undef,[{s,s,[<0.159.0>,update],[]}]}
=ERROR REPORT==== 29-Jan-2017::17:37:46 ===
Error in process <0.170.0> with exit value:
{undef,[{s,s,[<0.159.0>,update],[]}]}
=ERROR REPORT==== 29-Jan-2017::17:37:47 ===
Error in process <0.171.0> with exit value:
{undef,[{s,s,[<0.159.0>,update],[]}]}
=ERROR REPORT==== 29-Jan-2017::17:37:48 ===
Error in process <0.172.0> with exit value:
{undef,[{s,s,[<0.159.0>,update],[]}]}
=ERROR REPORT==== 29-Jan-2017::17:37:49 ===
Error in process <0.173.0> with exit value:
{undef,[{s,s,[<0.159.0>,update],[]}]}
=ERROR REPORT==== 29-Jan-2017::17:37:50 ===
Error in process <0.174.0> with exit value:
{undef,[{s,s,[<0.159.0>,update],[]}]}
Each go() function is just a convenience for
go() ->
gen_server:start_link(?MODULE, [], []).
Versioning:
Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
Eshell V8.2 (abort with ^G)
What happened?
EDIT:
s:s is from my shortcut module
-module(s).
-export([s/2]).
% Shortcuts.
% Send
s(Pid, Message) ->
gen_server:call(Pid, Message).
The update message is sent on a timer in the Room, which tries to send update to each of the Tables.
EDIT:
I have changed ZERO code. Here's what happens when I run now.. is this because I already have the *.beam files?
=ERROR REPORT==== 29-Jan-2017::17:50:19 ===
Error in process <0.200.0> with exit value:
{undef,[{s,s,[<0.59.0>,update],[]}]}
BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded
(v)ersion (k)ill (D)b-tables (d)istribution
^C~/tunnel:.ls
actions.beam clock.beam hall.beam s.erl table.erl
actions.erl clock.erl hall.erl seats.beam timer.erl
board.beam game.beam room.beam seats.erl
board.erl game.erl room.erl table.beam
~/tunnel:.erl
Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
Eshell V8.2 (abort with ^G)
1> c(board).
{ok,board}
2> c(all).
all.erl: no such file or directory
error
3> c().
** exception error: undefined shell command c/0
4> c(room).
{ok,room}
5> c(s).
{ok,s}
6> room:go().
{ok,<0.96.0>}
7>
BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded
(v)ersion (k)ill (D)b-tables (d)istribution
^C~/tunnel:.erl
Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
Eshell V8.2 (abort with ^G)
1> c(room).
{ok,room}
2> room:go().
{ok,<0.72.0>}
3> room:test().
All 4 tests passed.
ok
4>
BREAK: (a)bort (c)ontinue (p)roc info (i)nfo (l)oaded
(v)ersion (k)ill (D)b-tables (d)istribution
^C~/tunnel:.
~/tunnel:.erl
Erlang/OTP 19 [erts-8.2] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
Eshell V8.2 (abort with ^G)
1> c(room).
{ok,room}
2> room:go().
{ok,<0.72.0>}
3> room:test().
All 4 tests passed.
ok
4>
回答1:
It sounds to me like your module s was not compiled in the first case, especially give we can see you do compile it in your edit where the code works.
The error
=ERROR REPORT==== 29-Jan-2017::17:37:50 ===
Error in process <0.174.0> with exit value:
{undef,[{s,s,[<0.159.0>,update],[]}]}
is saying the call to module s and function s with the arguments <0.159.0> and update failed with undef.
Erlang will let you compile a module that has calls to as yet undefined functions, which is why we have tools like xref.
If you are not using a proper build tool like mix, rebar3 or erlang.mk I would advise you do.
来源：https://stackoverflow.com/questions/41926793/erlang-shell-stopped-loading-my-modules