diff --git a/main/fopen_wrappers.c b/main/fopen_wrappers.c
index fc0dbb9a984e..b01ae2d5045e 100644
--- a/main/fopen_wrappers.c
+++ b/main/fopen_wrappers.c
@@ -541,14 +541,14 @@ PHPAPI zend_string *php_resolve_path(const char *filename, size_t filename_lengt
 	ptr = path;
 	while (ptr && *ptr) {
 		/* Check for stream wrapper */
-		int is_stream_wrapper = 0;
+		bool is_stream_wrapper = false;
 
 		for (p = ptr; isalnum((int)*p) || *p == '+' || *p == '-' || *p == '.'; p++);
 		if ((*p == ':') && (p - ptr > 1) && (p[1] == '/') && (p[2] == '/')) {
 			/* .:// or ..:// is not a stream wrapper */
 			if (p[-1] != '.' || p[-2] != '.' || p - 2 != ptr) {
 				p += 3;
-				is_stream_wrapper = 1;
+				is_stream_wrapper = true;
 			}
 		}
 		end = strchr(p, DEFAULT_DIR_SEPARATOR);
diff --git a/main/main.c b/main/main.c
index 04715d1916ee..6d86ac09efbd 100644
--- a/main/main.c
+++ b/main/main.c
@@ -1010,10 +1010,10 @@ PHPAPI ZEND_COLD void php_verror(const char *docref, const char *params, int typ
 	const char *space = "";
 	const char *class_name = "";
 	const char *function;
-	int origin_len;
+	size_t origin_len;
 	char *origin;
 	zend_string *message;
-	int is_function = 0;
+	bool is_function = false;
 
 	/* get error text into buffer and escape for html if necessary */
 	zend_string *buffer = vstrpprintf(0, format, args);
@@ -1045,23 +1045,23 @@ PHPAPI ZEND_COLD void php_verror(const char *docref, const char *params, int typ
 		switch (EG(current_execute_data)->opline->extended_value) {
 			case ZEND_EVAL:
 				function = "eval";
-				is_function = 1;
+				is_function = true;
 				break;
 			case ZEND_INCLUDE:
 				function = "include";
-				is_function = 1;
+				is_function = true;
 				break;
 			case ZEND_INCLUDE_ONCE:
 				function = "include_once";
-				is_function = 1;
+				is_function = true;
 				break;
 			case ZEND_REQUIRE:
 				function = "require";
-				is_function = 1;
+				is_function = true;
 				break;
 			case ZEND_REQUIRE_ONCE:
 				function = "require_once";
-				is_function = 1;
+				is_function = true;
 				break;
 			default:
 				function = "Unknown";
@@ -1077,9 +1077,9 @@ PHPAPI ZEND_COLD void php_verror(const char *docref, const char *params, int typ
 
 	/* if we still have memory then format the origin */
 	if (is_function) {
-		origin_len = (int)spprintf(&origin, 0, "%s%s%s(%s)", class_name, space, function, params);
+		origin_len = spprintf(&origin, 0, "%s%s%s(%s)", class_name, space, function, params);
 	} else {
-		origin_len = (int)spprintf(&origin, 0, "%s", function);
+		origin_len = spprintf(&origin, 0, "%s", function);
 	}
 
 	if (PG(html_errors)) {
@@ -2093,13 +2093,13 @@ void dummy_invalid_parameter_handler(
 		unsigned int   line,
 		uintptr_t      pReserved)
 {
-	static int called = 0;
+	static bool called = false;
 	char buf[1024];
 	int len;
 
 	if (!called) {
 			if(PG(windows_show_crt_warning)) {
-			called = 1;
+			called = true;
 			if (function) {
 				if (file) {
 					len = _snprintf(buf, sizeof(buf)-1, "Invalid parameter detected in CRT function '%ws' (%ws:%u)", function, file, line);
@@ -2110,7 +2110,7 @@ void dummy_invalid_parameter_handler(
 				len = _snprintf(buf, sizeof(buf)-1, "Invalid CRT parameter detected (function not known)");
 			}
 			zend_error(E_WARNING, "%s", buf);
-			called = 0;
+			called = false;
 		}
 	}
 }
diff --git a/main/php_content_types.c b/main/php_content_types.c
index f01841986728..a481906a2c03 100644
--- a/main/php_content_types.c
+++ b/main/php_content_types.c
@@ -41,20 +41,17 @@ SAPI_API SAPI_POST_READER_FUNC(php_default_post_reader)
 /* }}} */
 
 /* {{{ php_startup_sapi_content_types */
-int php_startup_sapi_content_types(void)
+void php_startup_sapi_content_types(void)
 {
 	sapi_register_default_post_reader(php_default_post_reader);
 	sapi_register_treat_data(php_default_treat_data);
 	sapi_register_input_filter(php_default_input_filter, NULL);
-	return SUCCESS;
 }
 /* }}} */
 
 /* {{{ php_setup_sapi_content_types */
-int php_setup_sapi_content_types(void)
+void php_setup_sapi_content_types(void)
 {
 	sapi_register_post_entries(php_post_entries);
-
-	return SUCCESS;
 }
 /* }}} */
diff --git a/main/php_content_types.h b/main/php_content_types.h
index 6aab33e29421..261985c3ac01 100644
--- a/main/php_content_types.h
+++ b/main/php_content_types.h
@@ -21,7 +21,7 @@
 
 SAPI_API SAPI_POST_READER_FUNC(php_default_post_reader);
 SAPI_API SAPI_POST_HANDLER_FUNC(php_std_post_handler);
-int php_startup_sapi_content_types(void);
-int php_setup_sapi_content_types(void);
+void php_startup_sapi_content_types(void);
+void php_setup_sapi_content_types(void);
 
 #endif /* PHP_CONTENT_TYPES_H */
diff --git a/main/rfc1867.c b/main/rfc1867.c
index 84b8788bbf7c..cf234a2276dc 100644
--- a/main/rfc1867.c
+++ b/main/rfc1867.c
@@ -1214,7 +1214,7 @@ SAPI_API SAPI_POST_HANDLER_FUNC(rfc1867_post_handler)
 
 			{
 				zval file_size, error_type;
-				int size_overflow = 0;
+				bool size_overflow = false;
 				char file_size_buf[65];
 
 				ZVAL_LONG(&error_type, cancel_upload);
@@ -1235,7 +1235,7 @@ SAPI_API SAPI_POST_HANDLER_FUNC(rfc1867_post_handler)
 							file_size_buf[__len] = '\0';
 						}
 #endif
-						size_overflow = 1;
+						size_overflow = true;
 
 					} else {
 						ZVAL_LONG(&file_size, total_bytes);
diff --git a/main/streams/filter.c b/main/streams/filter.c
index abfc5c26ae12..276fcc94a9a1 100644
--- a/main/streams/filter.c
+++ b/main/streams/filter.c
@@ -70,7 +70,7 @@ PHPAPI int php_stream_filter_register_factory_volatile(zend_string *filterpatter
 
 PHPAPI php_stream_bucket *php_stream_bucket_new(php_stream *stream, char *buf, size_t buflen, uint8_t own_buf, uint8_t buf_persistent)
 {
-	int is_persistent = php_stream_is_persistent(stream);
+	bool is_persistent = php_stream_is_persistent(stream);
 	php_stream_bucket *bucket;
 
 	bucket = (php_stream_bucket*)pemalloc(sizeof(php_stream_bucket), is_persistent);
diff --git a/main/streams/memory.c b/main/streams/memory.c
index 785109db6582..f0fb6579eb13 100644
--- a/main/streams/memory.c
+++ b/main/streams/memory.c
@@ -619,7 +619,7 @@ static php_stream * php_stream_url_wrap_rfc2397(php_stream_wrapper *wrapper, con
 	size_t mlen, dlen, plen, vlen, ilen;
 	zend_off_t newoffs;
 	zval meta;
-	int base64 = 0;
+	bool base64 = false;
 	zend_string *base64_comma = NULL;
 
 	ZEND_ASSERT(mode);
diff --git a/main/streams/php_stream_filter_api.h b/main/streams/php_stream_filter_api.h
index ee6ab75f38c2..b982c8226468 100644
--- a/main/streams/php_stream_filter_api.h
+++ b/main/streams/php_stream_filter_api.h
@@ -45,7 +45,7 @@ struct _php_stream_bucket {
 	size_t buflen;
 	/* if non-zero, buf should be pefreed when the bucket is destroyed */
 	uint8_t own_buf;
-	uint8_t is_persistent;
+	bool is_persistent;
 
 	/* destroy this struct when refcount falls to zero */
 	int refcount;
diff --git a/main/streams/streams.c b/main/streams/streams.c
index 2eef790863f6..8df481b20a5f 100644
--- a/main/streams/streams.c
+++ b/main/streams/streams.c
@@ -2023,16 +2023,16 @@ PHPAPI php_stream_wrapper *php_stream_locate_url_wrapper(const char *path, const
 		php_stream_wrapper *plain_files_wrapper = (php_stream_wrapper*)&php_plain_files_wrapper;
 
 		if (protocol) {
-			int localhost = 0;
+			bool localhost = false;
 
 			if (!strncasecmp(path, "file://localhost/", 17)) {
-				localhost = 1;
+				localhost = true;
 			}
 
 #ifdef PHP_WIN32
 			if (localhost == 0 && path[n+3] != '\0' && path[n+3] != '/' && path[n+4] != ':')	{
 #else
-			if (localhost == 0 && path[n+3] != '\0' && path[n+3] != '/') {
+			if (localhost == false && path[n+3] != '\0' && path[n+3] != '/') {
 #endif
 				if (options & REPORT_ERRORS) {
 					php_error_docref(NULL, E_WARNING, "Remote host file access not supported, %s", path);