snippet once "Include header once only guard"
#ifndef ${1:`!p
if not snip.c:
	import random, string
	name = re.sub(r'[^A-Za-z0-9]+','_', snip.fn).upper()
	snip.rv = name.upper()
else:
    snip.rv = snip.c`}
#define $1

${0}

#endif /* !$1 */
endsnippet