escript:异常错误:不匹配右侧值{error，enoent}‏

Question

在Windows 7 (64位)上使用MinGW/MSYS构建Erlang RabbitMQ插件时，我遇到了上述错误。我正在使用Erlang v5.10.3 (32位)。我能够在我的系统上运行RabbitMQ。

Fujitsu@Notebook /d/RabbitMQ/build-source/rabbitmq-public-umbrella/presence-exchange-master
$ make
[elided] generate deps
escript: exception error: no match of right hand side value {error,enoent}
  in function  generate_deps__escript__1389__793192__493000:detect_deps/5 (d:/RabbitMQ/build-source/rabbitmq-public-umbrella/generate_deps, line 40)
  in call from generate_deps__escript__1389__793192__493000:'-main/1-fun-0-'/6 (d:/RabbitMQ/build-source/rabbitmq-public-umbrella/generate_deps, line 19)
  in call from lists:foldl/3 (lists.erl, line 1248)
  in call from generate_deps__escript__1389__793192__493000:main/1 (d:/RabbitMQ/build-source/rabbitmq-public-umbrella/generate_deps, line 17)
  in call from escript:run/2 (escript.erl, line 747)
  in call from escript:start/1 (escript.erl, line 277)
  in call from init:start_it/1 (init.erl, line 1054)
  in call from init:start_em/1 (init.erl, line 1034)

我已经在pastebin - http://pastebin.com/S739wfhB上发布了完整的错误，generate_deps的完整代码可以在这里找到- http://pastebin.com/N4HVz8z1

Ps。我也尝试过使用CYGWIN，但它返回另一个错误-转录:未能打开文件: /home/Fujitsu/rabbitmq/build-source/rabbitmq-public-umbrella/generate_deps

编辑1

CYGWIN返回：

$ make
[elided] generate deps
escript: Failed to open file: /cygdrive/d/RabbitMQ/build-source/rabbitmq-public-umbrella/generate_deps
[elided] generate deps
escript: Failed to open file: /cygdrive/d/RabbitMQ/build-source/rabbitmq-public-umbrella/generate_deps
make: *** No rule to make target 'build/deps.mk', needed by 'ebin/presence_exchange.beam'.  Stop.

但是，我可以使用head命令打开文件。

Fujitsu@Notebook /cygdrive/d/RabbitMQ/build-source/rabbitmq-public-umbrella/presence-exchange-master
$ head /cygdrive/d/RabbitMQ/build-source/rabbitmq-public-umbrella/generate_deps
#!/usr/bin/env escript
%% -*- erlang -*-
-mode(compile).

%% We expect the list of Erlang source and header files to arrive on
%% stdin, with the entries colon-separated.
main([TargetFile, EbinDir]) ->
    ErlsAndHrls = [ string:strip(S,left) ||
                      S <- string:tokens(io:get_line(""), ":\n")],
    ErlFiles = [F || F <- ErlsAndHrls, lists:suffix(".erl", F)],

Answer 1

这很可能是因为它找不到您要打开的文件，这就是POSIX enoent错误的含义。当你使用cygwin的时候，它就更明显了。erlang badmatch错误来自第23行：

{ok, Hdl} = file:open(TargetFile, [write, delayed_write]),

尝试打开文件并在{ok, Hld}上进行匹配的地方。但是，file:open在找不到文件时返回{error,enoent}，这将导致匹配失败并生成erlang错误。

编辑：

在我看来，问题在于它试图编写的文件。你可以在那个目录里写字吗？如果文件已经存在，是否允许打开它以进行写入？