Prism.languages.c = Prism.languages.extend('clike', {
	'comment': {
		pattern: /\/\/(?:[^\r\n\\]|\\(?:\r\n?|\n|(?![\r\n])))*|\/\*[\s\S]*?(?:\*\/|$)/,
		greedy: true
	},
	'class-name': {
		pattern: /(\b(?:enum|struct)\s+(?:__attribute__\s*\(\([\s\S]*?\)\)\s*)?)\w+/,
		lookbehind: true
	},
	'keyword': /\b(?:__attribute__|_Alignas|_Alignof|_Atomic|_Bool|_Complex|_Generic|_Imaginary|_Noreturn|_Static_assert|_Thread_local|asm|typeof|inline|auto|break|case|char|const|continue|default|do|double|else|enum|extern|float|for|goto|if|int|long|register|return|short|signed|sizeof|static|struct|switch|typedef|union|unsigned|void|volatile|while)\b/,
	'function': /[a-z_]\w*(?=\s*\()/i,
	'operator': />>=?|<<=?|->|([-+&|:])\1|[?:~]|[-+*/%&|^!=<>]=?/,
	'number': /(?:\b0x(?:[\da-f]+\.?[\da-f]*|\.[\da-f]+)(?:p[+-]?\d+)?|(?:\b\d+\.?\d*|\B\.\d+)(?:e[+-]?\d+)?)[ful]*/i
});

Prism.languages.insertBefore('c', 'string', {
	'macro': {
		// allow for multiline macro definitions
		// spaces after the # character compile fine with gcc
		pattern: /(^\s*)#\s*[a-z]+(?:[^\r\n\\/]|\/(?!\*)|\/\*(?:[^*]|\*(?!\/))*\*\/|\\(?:\r\n|[\s\S]))*/im,
		lookbehind: true,
		greedy: true,
		alias: 'property',
		inside: {
			'string': [
				{
					// highlight the path of the include statement as a string
					pattern: /^(#\s*include\s*)<[^>]+>/,
					lookbehind: true
				},
				Prism.languages.c['string']
			],
			'comment': Prism.languages.c['comment'],
			// highlight macro directives as keywords
			'directive': {
				pattern: /^(#\s*)[a-z]+/,
				lookbehind: true,
				alias: 'keyword'
			},
			'directive-hash': /^#/,
			'punctuation': /##|\\(?=[\r\n])/,
			'expression': {
				pattern: /\S[\s\S]*/,
				inside: Prism.languages.c
			}
		}
	},
	// highlight predefined macros as constants
	'constant': /\b(?:__FILE__|__LINE__|__DATE__|__TIME__|__TIMESTAMP__|__func__|EOF|NULL|SEEK_CUR|SEEK_END|SEEK_SET|stdin|stdout|stderr)\b/
});

delete Prism.languages.c['boolean'];