<p>Hello. I recently got a stack trace of my program. One of the lines in that trace said something like this.</p>
<pre><code>os/exec.(*Cmd).Wait(0xc420094840, 0x0, 0x0)
/usr/local/Cellar/go/1.7.1/libexec/src/os/exec/exec.go:442 +0x221
</code></pre>
<p>I wanted to edit that file to add a <code>fmt.Println</code> in order to print some info. So, I did just that and saved it.</p>
<p>However when I <code>go build</code> my program, my print statements never get called. I know I've done this before and it has worked. Did something change recently or is there a stdlib cache I can clear somewhere?</p>
<hr/>**评论：**<br/><br/>cs-guy: <pre><p>If it's been a while (say more than two years) since you have done this, then perhaps you used to use <code>go build -a</code>. The behavior of <code>go build -a</code> changed in <a href="https://golang.org/doc/go1.4" rel="nofollow">Go 1.4</a></p>
<blockquote>
<p>The behavior of the go build subcommand's -a flag has been changed for non-development installations. For installations running a released distribution, the -a flag will no longer rebuild the standard library and commands, to avoid overwriting the installation's files.</p>
</blockquote></pre>
