From b037b1b671d7069355fd146b9af110fc30c66afe Mon Sep 17 00:00:00 2001
From: Abdulaziz Ghuloum <aghuloum@cs.indiana.edu>
Date: Fri, 5 Dec 2008 02:19:26 -0500
Subject: [PATCH] getenv now returns #f for unset environment variables.

---
 scheme/ikarus.posix.ss | 13 ++++++++-----
 scheme/last-revision   |  2 +-
 src/ikarus-runtime.c   |  7 +------
 3 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/scheme/ikarus.posix.ss b/scheme/ikarus.posix.ss
index 991a9cd..b86d4a7 100644
--- a/scheme/ikarus.posix.ss
+++ b/scheme/ikarus.posix.ss
@@ -309,15 +309,18 @@
     ($file-time x 'file-mtime 
       (lambda (u) (foreign-call "ikrt_file_mtime2" u))))
 
-  (define ($getenv-bv key)
-    (foreign-call "ikrt_getenv" key))
-  (define ($getenv-str key) 
-    (utf8->string ($getenv-bv (string->utf8 key))))
+
 
   (define (getenv key)
+    (define who 'getenv)
+    (define ($getenv-str key) 
+      (define ($getenv-bv key)
+        (foreign-call "ikrt_getenv" key))
+      (let ([rv ($getenv-bv (string->utf8 key))])
+        (and rv (utf8->string rv))))
     (if (string? key)
         ($getenv-str key)
-        (die 'getenv "the key is not a string" key)))
+        (die who "key is not a string" key)))
 
   (define env
     (let ()
diff --git a/scheme/last-revision b/scheme/last-revision
index 7c024ac..4e43fed 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1697
+1698
diff --git a/src/ikarus-runtime.c b/src/ikarus-runtime.c
index 0e3456f..95e50a2 100644
--- a/src/ikarus-runtime.c
+++ b/src/ikarus-runtime.c
@@ -908,12 +908,7 @@ ikrt_getenv(ikptr bv, ikpcb* pcb){
     return s;
   } 
   else {
-    /* empty bv */
-    ikptr s = ik_safe_alloc(pcb, align(disp_bytevector_data+1)) 
-          + bytevector_tag;
-    ref(s, -bytevector_tag) = fix(0);
-    ref(s, off_bytevector_data) = 0;
-    return s;
+    return false_object;
   }
 }