diff --git a/codec/common/crt_util_safe_x.cpp b/codec/common/crt_util_safe_x.cpp
index 0fdc0d5e..aa90aaf3 100644
--- a/codec/common/crt_util_safe_x.cpp
+++ b/codec/common/crt_util_safe_x.cpp
@@ -234,6 +234,11 @@ int32_t WelsStrftime (str_t* pBuffer, int32_t iSize, const str_t* kpFormat, cons
 #endif
 
 
+str_t* WelsStrcat (str_t* pDest, int32_t iSizeInBytes, const str_t* kpSrc) {
+    int32_t iCurLen = strlen(pDest);
+    return WelsStrncpy(pDest + iCurLen, iSizeInBytes - iCurLen, kpSrc);
+}
+
 int32_t WelsFwrite (const void_t* kpBuffer, int32_t iSize, int32_t iCount, WelsFileHandle* pFp) {
   return fwrite (kpBuffer, iSize, iCount, pFp);
 }
diff --git a/codec/common/crt_util_safe_x.h b/codec/common/crt_util_safe_x.h
index 79ce3e88..c885dea5 100644
--- a/codec/common/crt_util_safe_x.h
+++ b/codec/common/crt_util_safe_x.h
@@ -77,7 +77,7 @@ typedef      struct timeb      SWelsTime;
 
 int32_t   WelsSnprintf (str_t* buffer,  int32_t sizeOfBuffer,  const str_t* format, ...);
 str_t*   WelsStrncpy (str_t* dest, int32_t sizeInBytes, const str_t* src);
-str_t*   WelsStrcat (str_t* dest, int32_t sizeInBytes, str_t* src);
+str_t*   WelsStrcat (str_t* dest, int32_t sizeInBytes, const str_t* src);
 int32_t   WelsVsnprintf (str_t* buffer, int32_t sizeOfBuffer, const str_t* format, va_list argptr);
 
 WelsFileHandle*        WelsFopen (const str_t* filename,  const str_t* mode);