diff --git a/src/common_define.h b/src/common_define.h
index bd374e9..cdcb40d 100644
--- a/src/common_define.h
+++ b/src/common_define.h
@@ -144,10 +144,10 @@ extern int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int kind);
 #define FC_IS_LETTER(ch)  ((ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z'))
 #define FC_IS_UPPER_LETTER(ch)  (ch >= 'A' && ch <= 'Z')
 #define FC_IS_LOWER_LETTER(ch)  (ch >= 'a' && ch <= 'z')
-#define FC_MIN(v1, v2) (v1 < v2 ? v1 : v2)
-#define FC_MAX(v1, v2) (v1 > v2 ? v1 : v2)
-#define FC_ABS(n) (n >= 0 ? (n) : -1 * (n))
-#define FC_NEGATIVE(n) (n <= 0 ? (n) : -1 * (n))
+#define FC_MIN(v1, v2) ((v1) < (v2) ? (v1) : (v2))
+#define FC_MAX(v1, v2) ((v1) > (v2) ? (v1) : (v2))
+#define FC_ABS(n) ((n) >= 0 ? (n) : -1 * (n))
+#define FC_NEGATIVE(n) ((n) <= 0 ? (n) : -1 * (n))
 
 #define FC_TIME_UNIT_SECOND   's'  //second
 #define FC_TIME_UNIT_MSECOND  'm'  //millisecond
diff --git a/src/fast_buffer.c b/src/fast_buffer.c
index d07ccec..1b8a755 100644
--- a/src/fast_buffer.c
+++ b/src/fast_buffer.c
@@ -62,8 +62,7 @@ int fast_buffer_set_capacity(FastBuffer *buffer, const int capacity)
     int new_capacity;
     char *buff;
 
-    new_capacity = (capacity > buffer->length) ?
-        capacity : (buffer->length + 1);
+    new_capacity = FC_MAX(capacity, buffer->length + 1);
     if (buffer->alloc_size >= new_capacity) {
         if (new_capacity > 1024) {
             alloc_size = 2048;