diff --git a/src/unix/os390-syscalls.c b/src/unix/os390-syscalls.c
index d753b129..1040d669 100644
--- a/src/unix/os390-syscalls.c
+++ b/src/unix/os390-syscalls.c
@@ -504,7 +504,7 @@ ssize_t os390_readlink(const char* path, char* buf, size_t len) {
 
 
 size_t strnlen(const char* str, size_t maxlen) {
-  void* p = memchr(str, 0, maxlen);
+  char* p = memchr(str, 0, maxlen);
   if (p == NULL)
     return maxlen;
   else