diff --git a/examples/stopwatch.h b/examples/stopwatch.h
index c153010a..96cc9757 100644
--- a/examples/stopwatch.h
+++ b/examples/stopwatch.h
@@ -30,7 +30,7 @@ static inline double StopwatchReadAndReset(Stopwatch* watch) {
 }
 
 
-#else    // !_WIN32
+#else    /* !_WIN32 */
 #include <sys/time.h>
 
 typedef struct timeval Stopwatch;
@@ -42,6 +42,6 @@ static inline double StopwatchReadAndReset(Stopwatch* watch) {
       (watch->tv_usec - old_value.tv_usec) / 1000000.0;
 }
 
-#endif   // !_WIN32
+#endif   /* _WIN32 */
 
-#endif  // WEBP_EXAMPLES_STOPWATCH_H_
+#endif  /* WEBP_EXAMPLES_STOPWATCH_H_ */
diff --git a/src/dec/webpi.h b/src/dec/webpi.h
index e2efb73d..b7336ecd 100644
--- a/src/dec/webpi.h
+++ b/src/dec/webpi.h
@@ -9,8 +9,8 @@
 //
 // Author: somnath@google.com (Somnath Banerjee)
 
-#ifndef WEBP_DEC_WEBPI_H
-#define WEBP_DEC_WEBPI_H
+#ifndef WEBP_DEC_WEBPI_H_
+#define WEBP_DEC_WEBPI_H_
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {
@@ -101,4 +101,4 @@ void WebPGrabDecBuffer(WebPDecBuffer* const src, WebPDecBuffer* const dst);
 }    // extern "C"
 #endif
 
-#endif  // WEBP_DEC_WEBPI_H
+#endif  /* WEBP_DEC_WEBPI_H_ */
diff --git a/src/dsp/dsp.h b/src/dsp/dsp.h
index ec49f490..d381a7d4 100644
--- a/src/dsp/dsp.h
+++ b/src/dsp/dsp.h
@@ -171,4 +171,4 @@ void WebPInitUpsamplers(void);
 }    // extern "C"
 #endif
 
-#endif  // WEBP_DSP_DSP_H_
+#endif  /* WEBP_DSP_DSP_H_ */
diff --git a/src/dsp/yuv.h b/src/dsp/yuv.h
index e438b61d..4fa9bedd 100644
--- a/src/dsp/yuv.h
+++ b/src/dsp/yuv.h
@@ -106,4 +106,4 @@ void VP8YUVInit(void);
 }    // extern "C"
 #endif
 
-#endif  // WEBP_DSP_YUV_H_
+#endif  /* WEBP_DSP_YUV_H_ */
diff --git a/src/enc/cost.h b/src/enc/cost.h
index 47dd6395..4b00c85b 100644
--- a/src/enc/cost.h
+++ b/src/enc/cost.h
@@ -51,4 +51,4 @@ extern const uint16_t VP8FixedCostsI4[NUM_BMODES][NUM_BMODES][NUM_BMODES];
 }    // extern "C"
 #endif
 
-#endif  // WEBP_ENC_COST_H_
+#endif  /* WEBP_ENC_COST_H_ */