diff --git a/crypto/bio/bss_log.c b/crypto/bio/bss_log.c
index f59ec7cce7a17a1bb3ea3b4c7f0494bd057532b2..a86ea29b6780c325f3beba9bef824bb0f227f882 100644
--- a/crypto/bio/bss_log.c
+++ b/crypto/bio/bss_log.c
@@ -322,7 +322,7 @@ static void xsyslog(BIO *bp, int priority, const char *string)
         break;
     }
 
-    sprintf(pidbuf, "[%u] ", GetCurrentProcessId());
+    sprintf(pidbuf, "[%lu] ", GetCurrentProcessId());
     lpszStrings[0] = pidbuf;
     lpszStrings[1] = string;