1 files changed, 1 insertions, 0 deletions
diff --git a/io.c b/io.c
index 40d8920081..184f0e6496 100644
--- a/io.c
+++ b/io.c
@@ -5444,6 +5444,7 @@ rb_sysopen(VALUE fname, int oflags, mode_t perm)
     struct sysopen_struct data;
 
     data.fname = rb_str_encode_ospath(fname);
+    StringValueCStr(data.fname);
     data.oflags = oflags;
     data.perm = perm;