diff --git a/src/c_api.h b/src/c_api.h
index d863d39ea173..03d06d3497aa 100644
--- a/src/c_api.h
+++ b/src/c_api.h
@@ -328,10 +328,10 @@ NCNN_EXPORT int ncnn_extractor_input_index(ncnn_extractor_t ex, int index, const
 NCNN_EXPORT int ncnn_extractor_extract_index(ncnn_extractor_t ex, int index, ncnn_mat_t* mat);
 
 /* mat process api */
-#define NCNN_BORDER_CONSTANT = 0,
-#define NCNN_BORDER_REPLICATE = 1,
-#define NCNN_BORDER_REFLECT = 2,
-#define NCNN_BORDER_TRANSPARENT = -233,
+#define NCNN_BORDER_CONSTANT 0
+#define NCNN_BORDER_REPLICATE 1
+#define NCNN_BORDER_REFLECT 2
+#define NCNN_BORDER_TRANSPARENT -233
 NCNN_EXPORT void ncnn_copy_make_border(const ncnn_mat_t src, ncnn_mat_t dst, int top, int bottom, int left, int right, int type, float v, const ncnn_option_t opt);
 NCNN_EXPORT void ncnn_copy_make_border_3d(const ncnn_mat_t src, ncnn_mat_t dst, int top, int bottom, int left, int right, int front, int behind, int type, float v, const ncnn_option_t opt);
 NCNN_EXPORT void ncnn_copy_cut_border(const ncnn_mat_t src, ncnn_mat_t dst, int top, int bottom, int left, int right, const ncnn_option_t opt);