Google now has a Code specific searching mechanism...

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Syntax and Examples (more about regexp syntax)
regexp	Search for a regular expression go{2}gle  hello,\ world  ^int printk
"exact string"	Search for exact string "compiler happy"
file:regexp	Search only in files or directories matching regexp file:\.js$ XMLHttpRequest  file:include/ ioctl file:/usr/sys/ken/slp.c "You are not expected to understand this."
package:regexp	Search packages with names matching regexp. (A package's name is its URL or CVS server information.) package:perl Frodo  package:linux-2.6 int\ printk
lang:regexp	Search only for programs written in languages matching regexp lang:lisp xml  lang:"c++" sprintf.*%s
license:regexp	Search only for files with licenses matching regexp. license:bsd int\ printf   -license:gpl heapsort

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