Fix c:nc to use outdir or cwd to find compiled object file

Before this patch, c:nc would naively assume the object file was created
in the same location as the .erl file. This is often false, for example
when an outdir is specified (often the case in make:all([netload])) or
calling with c:nc("foo/bar") (because compile:file places bar.beam in
the cwd, not foo/).

[ Squashed in minor style changes. /bg ]

2 files changed, 57 insertions, 4 deletions

diff --git a/lib/stdlib/src/c.erl b/lib/stdlib/src/c.erl
index 9e4cec5db2..433833e233 100644
--- a/lib/stdlib/src/c.erl
+++ b/lib/stdlib/src/c.erl
@@ -197,7 +197,9 @@ nc(File, Opts0) when is_list(Opts0) ->
     Opts = Opts0 ++ [report_errors, report_warnings],
     case compile:file(File, Opts) of
 	{ok,Mod} ->
-	    Fname = concat([File, code:objfile_extension()]),
+	    Dir = outdir(Opts),
+	    Obj = filename:basename(File, ".erl") ++ code:objfile_extension(),
+	    Fname = filename:join(Dir, Obj),
 	    case file:read_file(Fname) of
 		{ok,Bin} ->
 		    rpc:eval_everywhere(code,load_binary,[Mod,Fname,Bin]),
diff --git a/lib/stdlib/test/c_SUITE.erl b/lib/stdlib/test/c_SUITE.erl
index 5608d73d19..a2c8102393 100644
--- a/lib/stdlib/test/c_SUITE.erl
+++ b/lib/stdlib/test/c_SUITE.erl
@@ -18,15 +18,16 @@
 %%
 -module(c_SUITE).
 -export([all/1]).
--export([c_1/1, c_2/1, c_3/1, c_4/1, memory/1]).
+-export([c_1/1, c_2/1, c_3/1, c_4/1, nc_1/1, nc_2/1, nc_3/1, nc_4/1,
+         memory/1]).
 
 -include("test_server.hrl").
 
--import(c, [c/2]).
+-import(c, [c/2, nc/2]).
 
 all(doc) -> ["Test cases for the 'c' module."];
 all(suite) ->
-    [c_1, c_2, c_3, c_4, memory].
+    [c_1, c_2, c_3, c_4, nc_1, nc_2, nc_3, nc_4, memory].
 
 %%% Write output to a directory other than current directory:
 
@@ -78,6 +79,56 @@ c_4(Config) when list(Config) ->
     ?line Result = c(R,[{outdir,W}]),
     ?line {ok, m} = Result.
 
+%%% Write output to a directory other than current directory:
+
+nc_1(doc) ->
+    ["Checks that c:nc works also with option 'outdir'."];
+nc_1(suite) ->
+    [];
+nc_1(Config) when list(Config) ->
+    ?line R = filename:join(?config(data_dir, Config), "m.erl"),
+    ?line W = ?config(priv_dir, Config),
+    ?line Result = nc(R,[{outdir,W}]),
+    ?line {ok, m} = Result.
+
+nc_2(doc) ->
+    ["Checks that c:nc works also with option 'outdir'."];
+nc_2(suite) ->
+    [];
+nc_2(Config) when list(Config) ->
+    ?line R = filename:join(?config(data_dir, Config), "m"),
+    ?line W = ?config(priv_dir, Config),
+    ?line Result = nc(R,[{outdir,W}]),
+    ?line {ok, m} = Result.
+
+
+%%% Put results in current directory (or rather, change current dir
+%%% to the output dir):
+
+nc_3(doc) ->
+    ["Checks that c:nc works also with option 'outdir' (same as current"
+     "directory)."];
+nc_3(suite) ->
+    [];
+nc_3(Config) when list(Config) ->
+    ?line R = filename:join(?config(data_dir, Config), "m.erl"),
+    ?line W = ?config(priv_dir, Config),
+    ?line file:set_cwd(W),
+    ?line Result = nc(R,[{outdir,W}]),
+    ?line {ok, m} = Result.
+
+nc_4(doc) ->
+    ["Checks that c:nc works also with option 'outdir' (same as current"
+     "directory)."];
+nc_4(suite) ->
+    [];
+nc_4(Config) when list(Config) ->
+    ?line R = filename:join(?config(data_dir, Config), "m"),
+    ?line W = ?config(priv_dir, Config),
+    ?line file:set_cwd(W),
+    ?line Result = nc(R,[{outdir,W}]),
+    ?line {ok, m} = Result.
+
 memory(doc) ->
     ["Checks that c:memory/[0,1] returns consistent results."];
 memory(suite) ->