diff --git a/src/curl.cpp b/src/curl.cpp
index f0f6a66..6f5c1a6 100644
--- a/src/curl.cpp
+++ b/src/curl.cpp
@@ -199,6 +199,12 @@ const char* BodyData::str(void) const
 #define IAMCRED_EXPIRATION          "Expiration"
 #define IAMCRED_KEYCOUNT            4
 
+// [NOTICE]
+// This symbol is for libcurl under 7.23.0
+#ifndef CURLSHE_NOT_BUILT_IN
+#define CURLSHE_NOT_BUILT_IN        5
+#endif
+
 pthread_mutex_t  S3fsCurl::curl_handles_lock;
 pthread_mutex_t  S3fsCurl::curl_share_lock[SHARE_MUTEX_MAX];
 bool             S3fsCurl::is_initglobal_done  = false;
@@ -331,15 +337,21 @@ bool S3fsCurl::InitShareCurl(void)
     return false;
   }
   if(S3fsCurl::is_dns_cache){
-    if(CURLSHE_OK != (nSHCode = curl_share_setopt(S3fsCurl::hCurlShare, CURLSHOPT_SHARE, CURL_LOCK_DATA_DNS))){
+    nSHCode = curl_share_setopt(S3fsCurl::hCurlShare, CURLSHOPT_SHARE, CURL_LOCK_DATA_DNS);
+    if(CURLSHE_OK != nSHCode && CURLSHE_BAD_OPTION != nSHCode && CURLSHE_NOT_BUILT_IN != nSHCode){
       DPRN("curl_share_setopt(DNS) returns %d(%s)", nSHCode, curl_share_strerror(nSHCode));
       return false;
+    }else if(CURLSHE_BAD_OPTION == nSHCode || CURLSHE_NOT_BUILT_IN == nSHCode){
+      DPRN("curl_share_setopt(DNS) returns %d(%s), but continue without shared dns data.", nSHCode, curl_share_strerror(nSHCode));
     }
   }
   if(S3fsCurl::is_ssl_session_cache){
-    if(CURLSHE_OK != (nSHCode = curl_share_setopt(S3fsCurl::hCurlShare, CURLSHOPT_SHARE, CURL_LOCK_DATA_SSL_SESSION))){
+    nSHCode = curl_share_setopt(S3fsCurl::hCurlShare, CURLSHOPT_SHARE, CURL_LOCK_DATA_SSL_SESSION);
+    if(CURLSHE_OK != nSHCode && CURLSHE_BAD_OPTION != nSHCode && CURLSHE_NOT_BUILT_IN != nSHCode){
       DPRN("curl_share_setopt(SSL SESSION) returns %d(%s)", nSHCode, curl_share_strerror(nSHCode));
       return false;
+    }else if(CURLSHE_BAD_OPTION == nSHCode || CURLSHE_NOT_BUILT_IN == nSHCode){
+      DPRN("curl_share_setopt(SSL SESSION) returns %d(%s), but continue without shared ssl session data.", nSHCode, curl_share_strerror(nSHCode));
     }
   }
   if(CURLSHE_OK != (nSHCode = curl_share_setopt(S3fsCurl::hCurlShare, CURLSHOPT_USERDATA, (void*)&S3fsCurl::curl_share_lock[0]))){