diff --git a/src/3rdparty/md4c/md4c.c b/src/3rdparty/md4c/md4c.c
index 6aeef112e5..9d0d1b7d7b 100644
--- a/src/3rdparty/md4c/md4c.c
+++ b/src/3rdparty/md4c/md4c.c
@@ -916,7 +916,7 @@ md_merge_lines(MD_CTX* ctx, OFF beg, OFF end, const MD_LINE* lines, int n_lines,
         }
 
         if(off >= end) {
-            *p_size = ptr - buffer;
+            *p_size = (MD_SIZE)(ptr - buffer);
             return;
         }
 
@@ -2229,7 +2229,7 @@ md_is_link_reference(MD_CTX* ctx, const MD_LINE* lines, int n_lines,
 
     if(beg_line != end_line) {
         MD_CHECK(md_merge_lines_alloc(ctx, beg, end, beg_line,
-                 n_lines - (beg_line - lines), _T(' '), &label, &label_size));
+                 (int)(n_lines - (beg_line - lines)), _T(' '), &label, &label_size));
     } else {
         label = (CHAR*) STR(beg);
         label_size = end - beg;
@@ -4265,7 +4265,7 @@ md_process_inlines(MD_CTX* ctx, const MD_LINE* lines, int n_lines)
                     MD_CHECK(md_enter_leave_span_a(ctx, (mark->ch != ']'),
                                 (opener->ch == '!' ? MD_SPAN_IMG : MD_SPAN_A),
                                 STR(dest_mark->beg), dest_mark->end - dest_mark->beg, FALSE,
-                                md_mark_get_ptr(ctx, title_mark - ctx->marks), title_mark->prev));
+                                md_mark_get_ptr(ctx, (int)(title_mark - ctx->marks)), title_mark->prev));
 
                     /* link/image closer may span multiple lines. */
                     if(mark->ch == ']') {
@@ -4908,7 +4908,7 @@ md_push_block_bytes(MD_CTX* ctx, int n_bytes)
 
         /* Fix the ->current_block after the reallocation. */
         if(ctx->current_block != NULL) {
-            OFF off_current_block = (char*) ctx->current_block - (char*) ctx->block_bytes;
+            OFF off_current_block = (OFF)((char*) ctx->current_block - (char*) ctx->block_bytes);
             ctx->current_block = (MD_BLOCK*) ((char*) new_block_bytes + off_current_block);
         }