diff --git a/ext/ffi/ffi.c b/ext/ffi/ffi.c
index 06a79d250a633..2000e15c29ea1 100644
--- a/ext/ffi/ffi.c
+++ b/ext/ffi/ffi.c
@@ -4958,85 +4958,85 @@ ZEND_METHOD(FFI_CType, getFuncParameterType) /* {{{ */
 }
 /* }}} */
 
+static char *zend_ffi_skip_ws_and_comments(char *p, bool allow_standalone_newline)
+{
+	while (true) {
+		if (*p == ' ' || *p == '\t') {
+			p++;
+		} else if (allow_standalone_newline && (*p == '\r' || *p == '\n' || *p == '\f' || *p == '\v')) {
+			p++;
+		} else if (allow_standalone_newline && *p == '/' && p[1] == '/') {
+			p += 2;
+			while (*p && *p != '\r' && *p != '\n') {
+				p++;
+			}
+		} else if (*p == '/' && p[1] == '*') {
+			p += 2;
+			while (*p && (*p != '*' || p[1] != '/')) {
+				p++;
+			}
+			if (*p == '*') {
+				p++;
+				if (*p == '/') {
+					p++;
+				}
+			}
+		} else {
+			break;
+		}
+	}
+
+	return p;
+}
+
 static char *zend_ffi_parse_directives(const char *filename, char *code_pos, char **scope_name, char **lib, bool preload) /* {{{ */
 {
 	char *p;
 
+	code_pos = zend_ffi_skip_ws_and_comments(code_pos, true);
+
 	*scope_name = NULL;
 	*lib = NULL;
 	while (*code_pos == '#') {
-		if (strncmp(code_pos, "#define FFI_SCOPE", sizeof("#define FFI_SCOPE") - 1) == 0
-		 && (code_pos[sizeof("#define FFI_SCOPE") - 1] == ' '
-		  || code_pos[sizeof("#define FFI_SCOPE") - 1] == '\t')) {
-			p = code_pos + sizeof("#define FFI_SCOPE");
-			while (*p == ' ' || *p == '\t') {
-				p++;
-			}
-			if (*p != '"') {
-				if (preload) {
-					zend_error(E_WARNING, "FFI: failed pre-loading '%s', bad FFI_SCOPE define", filename);
-				} else {
-					zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', bad FFI_SCOPE define", filename);
-				}
-				return NULL;
-			}
-			p++;
-			if (*scope_name) {
-				if (preload) {
-					zend_error(E_WARNING, "FFI: failed pre-loading '%s', FFI_SCOPE defined twice", filename);
-				} else {
-					zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', FFI_SCOPE defined twice", filename);
-				}
-				return NULL;
-			}
-			*scope_name = p;
-			while (1) {
-				if (*p == '\"') {
-					*p = 0;
+		if (strncmp(code_pos, ZEND_STRL("#define")) == 0) {
+			p = zend_ffi_skip_ws_and_comments(code_pos + sizeof("#define") - 1, false);
+
+			char **target = NULL;
+			const char *target_name = NULL;
+			if (strncmp(p, ZEND_STRL("FFI_SCOPE")) == 0) {
+				p = zend_ffi_skip_ws_and_comments(p + sizeof("FFI_SCOPE") - 1, false);
+				target = scope_name;
+				target_name = "FFI_SCOPE";
+			} else if (strncmp(p, ZEND_STRL("FFI_LIB")) == 0) {
+				p = zend_ffi_skip_ws_and_comments(p + sizeof("FFI_LIB") - 1, false);
+				target = lib;
+				target_name = "FFI_LIB";
+			} else {
+				while (*p && *p != '\n' && *p != '\r') {
 					p++;
-					break;
-				} else if (*p <= ' ') {
-					if (preload) {
-						zend_error(E_WARNING, "FFI: failed pre-loading '%s', bad FFI_SCOPE define", filename);
-					} else {
-						zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', bad FFI_SCOPE define", filename);
-					}
-					return NULL;
 				}
-				p++;
-			}
-			while (*p == ' ' || *p == '\t') {
-				p++;
-			}
-			while (*p == '\r' || *p == '\n') {
-				p++;
-			}
-			code_pos = p;
-		} else if (strncmp(code_pos, "#define FFI_LIB", sizeof("#define FFI_LIB") - 1) == 0
-		 && (code_pos[sizeof("#define FFI_LIB") - 1] == ' '
-		  || code_pos[sizeof("#define FFI_LIB") - 1] == '\t')) {
-			p = code_pos + sizeof("#define FFI_LIB");
-			while (*p == ' ' || *p == '\t') {
-				p++;
+				code_pos = zend_ffi_skip_ws_and_comments(p, true);
+				continue;
 			}
+
 			if (*p != '"') {
 				if (preload) {
-					zend_error(E_WARNING, "FFI: failed pre-loading '%s', bad FFI_LIB define", filename);
+					zend_error(E_WARNING, "FFI: failed pre-loading '%s', bad %s define", filename, target_name);
 				} else {
-					zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', bad FFI_LIB define", filename);
+					zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', bad %s define", filename, target_name);
 				}
 				return NULL;
 			}
 			p++;
-			if (*lib) {
+			if (*target) {
 				if (preload) {
-					zend_error(E_WARNING, "FFI: failed pre-loading '%s', FFI_LIB defined twice", filename);
+					zend_error(E_WARNING, "FFI: failed pre-loading '%s', %s defined twice", filename, target_name);
 				} else {
-					zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', FFI_LIB defined twice", filename);
+					zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', %s defined twice", filename, target_name);
 				}
 				return NULL;
 			}
-			*lib = p;
+			*target = p;
 			while (1) {
 				if (*p == '\"') {
 					*p = 0;
@@ -5044,21 +5044,16 @@ static char *zend_ffi_parse_directives(const char *filename, char *code_pos, cha
 					break;
 				} else if (*p <= ' ') {
 					if (preload) {
-						zend_error(E_WARNING, "FFI: failed pre-loading '%s', bad FFI_LIB define", filename);
+						zend_error(E_WARNING, "FFI: failed pre-loading '%s', bad %s define", filename, target_name);
 					} else {
-						zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', bad FFI_LIB define", filename);
+						zend_throw_error(zend_ffi_exception_ce, "Failed loading '%s', bad %s define", filename, target_name);
 					}
 					return NULL;
 				}
 				p++;
 			}
-			while (*p == ' ' || *p == '\t') {
-				p++;
-			}
-			while (*p == '\r' || *p == '\n') {
-				p++;
-			}
-			code_pos = p;
+
+			code_pos = zend_ffi_skip_ws_and_comments(p, true);
 		} else {
 			break;
 		}
diff --git a/ext/ffi/tests/bug79075.h b/ext/ffi/tests/bug79075.h
new file mode 100644
index 0000000000000..22fa6067a347a
--- /dev/null
+++ b/ext/ffi/tests/bug79075.h
@@ -0,0 +1,12 @@
+/*
+ * Multiline comment
+ */
+  // whitespace line
+
+#define ignore_this_line 1
+  //
+#define/* inline */FFI_SCOPE /* multi-
+line */ "bug79075" /* end
+*/
+
+int printf(const char *format, ...);
diff --git a/ext/ffi/tests/bug79075.inc b/ext/ffi/tests/bug79075.inc
new file mode 100644
index 0000000000000..ab3daa93d4de3
--- /dev/null
+++ b/ext/ffi/tests/bug79075.inc
@@ -0,0 +1,3 @@
+<?php
+
+FFI::load(__DIR__ . "/bug79075.h");
diff --git a/ext/ffi/tests/bug79075.phpt b/ext/ffi/tests/bug79075.phpt
new file mode 100644
index 0000000000000..70f3045aca1ff
--- /dev/null
+++ b/ext/ffi/tests/bug79075.phpt
@@ -0,0 +1,25 @@
+--TEST--
+Bug #79075 (FFI header parser chokes on comments)
+--EXTENSIONS--
+ffi
+opcache
+posix
+--SKIPIF--
+<?php
+if (substr(PHP_OS, 0, 3) == 'WIN') die('skip not for Windows');
+if (posix_geteuid() == 0) die('skip Cannot run test as root.');
+?>
+--INI--
+ffi.enable=1
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=-1
+opcache.preload={PWD}/bug79075.inc
+opcache.file_cache_only=0
+--FILE--
+<?php
+$ffi = FFI::scope("bug79075");
+$ffi->printf("Hello World from %s!\n", "PHP");
+?>
+--EXPECT--
+Hello World from PHP!