diff --git a/include/ma_global.h b/include/ma_global.h
index 5699aefe..bcb1b70c 100644
--- a/include/ma_global.h
+++ b/include/ma_global.h
@@ -336,7 +336,14 @@ typedef unsigned short ushort;
 
 typedef int	File;		/* File descriptor */
 #ifndef my_socket_defined
-typedef int	my_socket;	/* File descriptor for sockets */
+#define my_socket_defined
+#if defined(_WIN64)
+#define my_socket unsigned long long
+#elif defined(_WIN32)
+#define my_socket unsigned int
+#else
+typedef int my_socket;
+#endif
 #define my_socket_defined
 #endif
 #ifndef INVALID_SOCKET
diff --git a/include/mysql.h b/include/mysql.h
index 8c8e60e9..ca1b8d22 100644
--- a/include/mysql.h
+++ b/include/mysql.h
@@ -717,8 +717,8 @@ struct st_mariadb_api {
   my_bool (STDCALL *mysql_rollback)(MYSQL *mysql);
   unsigned long long (STDCALL *mysql_insert_id)(MYSQL *mysql);
   unsigned int (STDCALL *mysql_errno)(MYSQL *mysql);
-  char * (STDCALL *mysql_error)(MYSQL *mysql);
-  char * (STDCALL *mysql_info)(MYSQL *mysql);
+  const char * (STDCALL *mysql_error)(MYSQL *mysql);
+  const char * (STDCALL *mysql_info)(MYSQL *mysql);
   unsigned long (STDCALL *mysql_thread_id)(MYSQL *mysql);
   const char * (STDCALL *mysql_character_set_name)(MYSQL *mysql);
   void (STDCALL *mysql_get_character_set_info)(MYSQL *mysql, MY_CHARSET_INFO *cs);
diff --git a/libmariadb/ma_dtoa.c b/libmariadb/ma_dtoa.c
index bfc0c962..e45f7927 100644
--- a/libmariadb/ma_dtoa.c
+++ b/libmariadb/ma_dtoa.c
@@ -108,7 +108,7 @@ size_t ma_fcvt(double x, int precision, char *to, my_bool *error)
   }
 
   src= res;
-  len= end - src;
+  len= (int)(end - src);
 
   if (sign)
     *dst++= '-';
@@ -240,7 +240,7 @@ size_t ma_gcvt(double x, my_gcvt_arg_type type, int width, char *to,
     *error= FALSE;
 
   src= res;
-  len= end - res;
+  len= (int)(end - res);
 
   /*
     Number of digits in the exponent from the 'e' conversion.
@@ -332,7 +332,7 @@ size_t ma_gcvt(double x, my_gcvt_arg_type type, int width, char *to,
       dtoa_free(res, buf, sizeof(buf));
       res= dtoa(x, 5, width - decpt, &decpt, &sign, &end, buf, sizeof(buf));
       src= res;
-      len= end - res;
+      len= (int)(end - res);
     }
 
     if (len == 0)
@@ -398,7 +398,7 @@ size_t ma_gcvt(double x, my_gcvt_arg_type type, int width, char *to,
       dtoa_free(res, buf, sizeof(buf));
       res= dtoa(x, 4, width, &decpt, &sign, &end, buf, sizeof(buf));
       src= res;
-      len= end - res;
+      len= (int)(end - res);
       if (--decpt < 0)
         decpt= -decpt;
     }
diff --git a/libmariadb/ma_stmt_codec.c b/libmariadb/ma_stmt_codec.c
index 66672803..c6fe3ce8 100644
--- a/libmariadb/ma_stmt_codec.c
+++ b/libmariadb/ma_stmt_codec.c
@@ -594,7 +594,7 @@ static void convert_from_float(MYSQL_BIND *r_param, const MYSQL_FIELD *field, fl
 
       if (field->decimals >= NOT_FIXED_DEC)
       {
-        length= ma_gcvt(val, MY_GCVT_ARG_FLOAT, length, buff, NULL);
+        length= ma_gcvt(val, MY_GCVT_ARG_FLOAT, (int)length, buff, NULL);
       }
       else
       {
@@ -693,7 +693,7 @@ static void convert_from_double(MYSQL_BIND *r_param, const MYSQL_FIELD *field, d
 
      if (field->decimals >= NOT_FIXED_DEC)
      {
-       length= ma_gcvt(val, MY_GCVT_ARG_DOUBLE, length, buff, NULL);
+       length= ma_gcvt(val, MY_GCVT_ARG_DOUBLE, (int)length, buff, NULL);
      }
      else
      {
@@ -851,7 +851,7 @@ void ps_fetch_datetime(MYSQL_BIND *r_param, const MYSQL_FIELD * field,
   {
     char dtbuffer[60];
     MYSQL_TIME tm;
-    unsigned int length;
+    size_t length;
     convert_to_datetime(&tm, row, len, field->type);
  /*   
     if (tm.time_type== MYSQL_TIMESTAMP_TIME && tm.day)
diff --git a/libmariadb/mariadb_lib.c b/libmariadb/mariadb_lib.c
index c1b42e05..6780949a 100644
--- a/libmariadb/mariadb_lib.c
+++ b/libmariadb/mariadb_lib.c
@@ -2703,12 +2703,12 @@ mysql_optionsv(MYSQL *mysql,enum mysql_option option, ...)
     break;
   case MYSQL_OPT_MAX_ALLOWED_PACKET:
     if (mysql)
-      mysql->options.max_allowed_packet= (*(size_t *)arg1);
+      mysql->options.max_allowed_packet= (unsigned long)(*(size_t *)arg1);
     else
-      max_allowed_packet= (*(size_t *)arg1);
+      max_allowed_packet= (unsigned long)(*(size_t *)arg1);
     break;
   case MYSQL_OPT_NET_BUFFER_LENGTH:
-    net_buffer_length= (*(size_t *)arg1);
+    net_buffer_length= (unsigned long)(*(size_t *)arg1);
     break;
   case MYSQL_OPT_SSL_ENFORCE:
     mysql->options.use_ssl= (*(my_bool *)arg1);
diff --git a/libmariadb/mariadb_stmt.c b/libmariadb/mariadb_stmt.c
index 8508a67a..4f407235 100644
--- a/libmariadb/mariadb_stmt.c
+++ b/libmariadb/mariadb_stmt.c
@@ -565,7 +565,7 @@ int store_param(MYSQL_STMT *stmt, int column, unsigned char **p, unsigned long r
       len= (ulong)STMT_NUM_OFS(long, stmt->params[column].length, row_nr);
 
     if ((long)len == STMT_INDICATOR_NTS)
-      len= strlen((char *)buf);
+      len= (ulong)strlen((char *)buf);
     to = mysql_net_store_length(*p, len);
 
     if (len)
@@ -700,7 +700,7 @@ unsigned char* mysql_stmt_execute_generate_request(MYSQL_STMT *stmt, size_t *req
     {
       for (i=0; i < stmt->param_count; i++)
       {
-        ulong size= 0;
+        size_t size= 0;
         my_bool has_data= TRUE;
         char indicator= 0;
 
diff --git a/plugins/auth/sspi_errmsg.c b/plugins/auth/sspi_errmsg.c
index 5e212bfb..558bedcb 100644
--- a/plugins/auth/sspi_errmsg.c
+++ b/plugins/auth/sspi_errmsg.c
@@ -138,7 +138,7 @@ void sspi_errmsg(int err, char *buf, size_t size)
   len = FormatMessageA(
     FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL,
     err, MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
-    buf, size, NULL);
+    buf, (DWORD)size, NULL);
 
   if(len > 0)
   {
diff --git a/unittest/libmariadb/bulk1.c b/unittest/libmariadb/bulk1.c
index 612b9aac..9454af71 100644
--- a/unittest/libmariadb/bulk1.c
+++ b/unittest/libmariadb/bulk1.c
@@ -179,7 +179,7 @@ static int bulk3(MYSQL *mysql)
   MYSQL_STMT *stmt= mysql_stmt_init(mysql);
   size_t row_size= sizeof(struct st_bulk3);
   int array_size= 3;
-  size_t length= -1;
+  ulong length= -1;
 
   rc= mysql_query(mysql, "DROP TABLE IF EXISTS bulk3");
   check_mysql_rc(rc,mysql);
diff --git a/unittest/libmariadb/features-10_2.c b/unittest/libmariadb/features-10_2.c
index 1910bcfc..3ae63f92 100644
--- a/unittest/libmariadb/features-10_2.c
+++ b/unittest/libmariadb/features-10_2.c
@@ -190,7 +190,7 @@ static int com_multi_ps2(MYSQL *mysql)
   bind[0].buffer= &intval;
   bind[1].buffer_type= MYSQL_TYPE_STRING;
   bind[1].buffer= (char *)varval;
-  bind[1].buffer_length= strlen(varval);
+  bind[1].buffer_length= (ulong)strlen(varval);
 
   stmt= mysql_stmt_init(mysql);
   mysql_stmt_attr_set(stmt, STMT_ATTR_PREBIND_PARAMS, &param_count);
@@ -284,7 +284,7 @@ static int execute_direct_example(MYSQL *mysql)
   bind[0].buffer= &intval;
   bind[1].buffer_type= MYSQL_TYPE_STRING;
   bind[1].buffer= (char *)strval;
-  bind[1].buffer_length= strlen(strval);
+  bind[1].buffer_length= (ulong)strlen(strval);
 
   /* set number of parameters */
   if (mysql_stmt_attr_set(stmt, STMT_ATTR_PREBIND_PARAMS, &param_count))
diff --git a/unittest/libmariadb/ps.c b/unittest/libmariadb/ps.c
index 9965e48d..2a1488c6 100644
--- a/unittest/libmariadb/ps.c
+++ b/unittest/libmariadb/ps.c
@@ -3418,7 +3418,7 @@ static int test_double_compare(MYSQL *mysql)
 
   tiny_data= 1;
   strcpy(real_data, "10.2");
-  length[1]= strlen(real_data);
+  length[1]= (ulong)strlen(real_data);
   double_data= 34.5;
   rc= mysql_stmt_bind_param(stmt, my_bind);
   check_stmt_rc(rc, stmt);