gistfile1.xml

<snippet>
	<content><![CDATA[
#ifndef ${TM_FILEPATH/(([A-Za-z]+)\/src\/)|./\U(?1:$2_)\E/g}${TM_FILENAME/(([A-Z])([A-Z][a-z]))|(([a-z])([A-Z]))|([a-z])|(\.)/\U(?1:$2_$3)(?4:$5_$6)$7(?8:_)\E/g}
#define ${TM_FILEPATH/(([A-Za-z]+)\/src\/)|./\U(?1:$2_)\E/g}${TM_FILENAME/(([A-Z])([A-Z][a-z]))|(([a-z])([A-Z]))|([a-z])|(\.)/\U(?1:$2_$3)(?4:$5_$6)$7(?8:_)\E/g}

$0

#endif
]]></content>
	<!-- Optional: Set a tabTrigger to define how to trigger the snippet -->
	<tabTrigger>guard</tabTrigger>
	<!-- Optional: Set a scope to limit where the snippet will trigger -->
	<scope>source.c++</scope>
	<scope>source.c</scope>
</snippet>