From f1c82f55b9ac75e6bb965c7e9c26668db2b02a2e Mon Sep 17 00:00:00 2001
From: Kevin Ryde <user42@zip.com.au>
Date: Tue, 7 Sep 2004 00:06:18 +0000
Subject: [PATCH] (scm_nice): Correction to error detection.  Reported by
 Matthias Koeppe.

---
 libguile/posix.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libguile/posix.c b/libguile/posix.c
index d9cfb529c..35f61037e 100644
--- a/libguile/posix.c
+++ b/libguile/posix.c
@@ -1422,7 +1422,11 @@ SCM_DEFINE (scm_nice, "nice", 1, 0, 0,
 	    "The return value is unspecified.")
 #define FUNC_NAME s_scm_nice
 {
-  if (nice (scm_to_int (incr)) != 0)
+  /* nice() returns "prio-NZERO" on success or -1 on error, but -1 can arise
+     from "prio-NZERO", so an error must be detected from errno changed */
+  errno = 0;
+  nice (scm_to_int (incr));
+  if (errno != 0)
     SCM_SYSERROR;
   return SCM_UNSPECIFIED;
 }