io.c: reduce isatty on Cygwin [ci skip]

* io.c (prep_io): reduce isatty call (and its system call) on
  Cygwin.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56383 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 7 deletions

diff --git a/io.c b/io.c
index e9ff6f5ff9..17ec6baa81 100644
--- a/io.c
+++ b/io.c
@@ -5518,11 +5518,13 @@ rb_fdopen(int fd, const char *modestr)
     return file;
 }
 
-static void
+static int
 io_check_tty(rb_io_t *fptr)
 {
-    if (isatty(fptr->fd))
+    int t = isatty(fptr->fd);
+    if (t)
         fptr->mode |= FMODE_TTY|FMODE_DUPLEX;
+    return t;
 }
 
 static VALUE rb_io_internal_encoding(VALUE);
@@ -7370,14 +7372,13 @@ prep_io(int fd, int fmode, VALUE klass, const char *path)
 
     MakeOpenFile(io, fp);
     fp->fd = fd;
+    fp->mode = fmode;
+    if (!io_check_tty(fp)) {
 #ifdef __CYGWIN__
-    if (!isatty(fd)) {
-        fmode |= FMODE_BINMODE;
+	fp->fmode |= FMODE_BINMODE;
 	setmode(fd, O_BINARY);
-    }
 #endif
-    fp->mode = fmode;
-    io_check_tty(fp);
+    }
     if (path) fp->pathv = rb_obj_freeze(rb_str_new_cstr(path));
     rb_update_max_fd(fd);