py, unix: Allow to compile with -Wsign-compare.

See issue #699.

1 files changed, 1 insertions, 1 deletions

diff --git a/py/vstr.c b/py/vstr.c
index e87aef9e4..1f9f13637 100644
--- a/py/vstr.c
+++ b/py/vstr.c
@@ -350,7 +350,7 @@ void vstr_vprintf(vstr_t *vstr, const char *fmt, va_list ap) {
         va_end(ap2);
 
         // if that worked, return
-        if (n > -1 && n < size) {
+        if (n > -1 && (size_t)n < size) {
             vstr->len += n;
             return;
         }