Comment 1:

The +build lines need to come "early" in the file.  Try moving the +build lines above
the large copyright block and report back if that fixes it for you.

Status changed to WaitingForReply.

Comment 2:

I moved the +build line to the first line and it still failed.

Comment 3:

Try
// +build freebsd netbsd openbsd
at the top of the file.

Comment 4:

I added the "// +build freebsd netbsd openbsd" to the top of the file and it still
fails. 
I then added "// +build freebsd netbsd openbsd !windows" and it also failed.
Ironically, its just the zmq_bsd.go that is failing. If I leave the zmq_linux.go there
and remove the zmq_bsd.go, it will compile.

Comment 5:

Your zmq_bsd.go file starts with:
>>>
/*
  Copyright 2012 Alec Thomas
  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.
*/
// For some reason, Go on Windows tries to build both this file and zmq_windows.go.
// +build !windows
<<<
This contradicts http://golang.org/pkg/go/build/#Build_Constraints:
... Constraints may appear in any kind of source file (not just Go), but they must be
appear near the top of the file, preceded only by blank lines and other line comments. 
...
You have "general comment", not "line comment", in front of your build constrain. Follow
Brad's advice, move "// +build !windows" line to the beginning of the file.
Alex

Status changed to WorkingAsIntended.

Comment 6:

Ah, I see. It was missing an extra new line after the +build line.
This works:
// +build !windows
/*
This doesn't:
// +build !windows
/*

Comment 7:

You are correct. It seems go needs blank line after "// +build !windows". I can't find
any doco for that. Perhaps, this needs to be clarified. Leaving for others to decide.
Thank you.
Alex

Comment 8:

Thank you very much for diagnosing that problem.
// +build foo
/*
other comment
*/
is supposed to work.

Labels changed: added priority-soon, removed priority-triage.

Status changed to Accepted.

Comment 9:

I don't think that's right. Godoc will likely get the synopsis wrong
for the following if we allow build directives without a subsequent
blank line.
// +build foo
/*
Package lorem ipsum dolor set
*/
package lorem

Comment 10:

Godoc is a different program.  Not all /* */ comments are package comments.

Comment 11:

I believe this is correct behavior now, but we need to document the behavior.

Comment 12:

Issue #3730 has been merged into this issue.

Comment 13 by seed@mail.nanosouffle.net:

rsc wrote:
> I believe this is correct behavior now, but we need to document the behavior.
Which behaviour? I don't think the format:
"// +build foo
/*
other comment
*/
package bar"
works yet. I feel that it should.
I feel that in general, a `+build'
directive as the very first line
in the file should be taken into
account.
What do you feel about this?

Comment 14:

Labels changed: added go1.1.

Comment 15:

I don't expect that to work. The rule is that it must be followed by a
blank line. The // +build parser intentionally does not know what a /*
*/ comment is.

Comment 16:

Labels changed: added size-m.

Comment 17:

Labels changed: added suggested.

Comment 18:

This issue was closed by revision 2e51f78.

Status changed to Fixed.

Comment 19:

Issue #4985 has been merged into this issue.