diff --git a/src/s3fs_cred.cpp b/src/s3fs_cred.cpp
index 2a94280..2de2bae 100644
--- a/src/s3fs_cred.cpp
+++ b/src/s3fs_cred.cpp
@@ -99,23 +99,17 @@ bool S3fsCred::ParseIAMRoleFromMetaDataResponse(const char* response, std::strin
 //-------------------------------------------------------------------
 S3fsCred::S3fsCred() :
     is_lock_init(false),
-    passwd_file(""),
     aws_profile(DEFAULT_AWS_PROFILE_NAME),
     load_iamrole(false),
-    AWSAccessKeyId(""),
-    AWSSecretAccessKey(""),
-    AWSAccessToken(""),
     AWSAccessTokenExpire(0),
     is_ecs(false),
     is_use_session_token(false),
     is_ibm_iam_auth(false),
     IAM_cred_url("http://169.254.169.254/latest/meta-data/iam/security-credentials/"),
     IAM_api_version(2),
-    IAMv2_api_token(""),
     IAM_field_count(4),
     IAM_token_field("Token"),
-    IAM_expiry_field("Expiration"),
-    IAM_role("")
+    IAM_expiry_field("Expiration")
 {
     pthread_mutexattr_t attr;
     pthread_mutexattr_init(&attr);
diff --git a/src/s3fs_cred.h b/src/s3fs_cred.h
index 8ed15c6..8884166 100644
--- a/src/s3fs_cred.h
+++ b/src/s3fs_cred.h
@@ -119,7 +119,7 @@ class S3fsCred
         bool ParseS3fsPasswdFile(bucketkvmap_t& resmap);
         bool ReadS3fsPasswdFile(AutoLock::Type type);
 
-        int CheckS3fsCredentialAwsFormat(const kvmap_t& kvmap, std::string& access_key_id, std::string& secret_access_key);
+        static int CheckS3fsCredentialAwsFormat(const kvmap_t& kvmap, std::string& access_key_id, std::string& secret_access_key);
         bool ReadAwsCredentialFile(const std::string &filename, AutoLock::Type type);
 
         bool InitialS3fsCredentials();
@@ -130,7 +130,7 @@ class S3fsCred
         bool SetIAMCredentials(const char* response, AutoLock::Type type);
         bool SetIAMRoleFromMetaData(const char* response, AutoLock::Type type);
 
-        bool CheckForbiddenBucketParams();
+        static bool CheckForbiddenBucketParams();
 
     public:
         static bool SetBucket(const char* bucket);
diff --git a/src/threadpoolman.cpp b/src/threadpoolman.cpp
index db4f47d..bed3826 100644
--- a/src/threadpoolman.cpp
+++ b/src/threadpoolman.cpp
@@ -216,7 +216,8 @@ bool ThreadPoolMan::StopThreads()
     thread_list.clear();
 
     // reset semaphore(to zero)
-    while(thpoolman_sem.try_wait());
+    while(thpoolman_sem.try_wait()){
+    }
 
     // clear instructions
     for(thpoolman_params_t::const_iterator iter = instruction_list.begin(); iter != instruction_list.end(); ++iter){