--- /dev/null
+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1994
+%
+\subsection[getBufferMode.lc]{hIs...Buffered Runtime Support}
+
+\begin{code}
+
+#include "rtsdefs.h"
+#include "stgio.h"
+
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#ifdef HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+
+/*
+ * We try to guess what the default buffer mode is going to be based
+ * on the type of file we're attached to.
+ */
+
+#define GBM_NB (0)
+#define GBM_LB (-1)
+#define GBM_BB (-2)
+#define GBM_ERR (-3)
+
+StgInt
+getBufferMode(fp)
+StgForeignObj fp;
+{
+ struct stat sb;
+
+ /* Try to find out the file type */
+ while (fstat(fileno((FILE *) fp), &sb) < 0) {
+ /* highly unlikely */
+ if (errno != EINTR) {
+ cvtErrno();
+ stdErrno();
+ return GBM_ERR;
+ }
+ }
+ /* Terminals are line-buffered by default */
+ if (S_ISCHR(sb.st_mode) && isatty(fileno((FILE *) fp)) == 1)
+ return GBM_LB;
+ /* Default size block buffering for the others */
+ else
+ return GBM_BB;
+}
+
+\end{code}