diff --git a/src/port/thread.c b/src/port/thread.c
index 80af433e4ac0735dc5c36a29b84f9cac4b535600..8446f01f8aa5512aa2edd268046c3f89742d2f35 100644
--- a/src/port/thread.c
+++ b/src/port/thread.c
@@ -7,7 +7,7 @@
  *
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  *
- * $Id: thread.c,v 1.4 2003/08/16 15:35:51 momjian Exp $
+ * $Id: thread.c,v 1.5 2003/09/03 19:30:31 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -39,6 +39,8 @@
  *	The current setup is to assume either all standard functions are
  *	thread-safe (NEED_REENTRANT_FUNC_NAMES=no), or the operating system
  *	requires reentrant function names (NEED_REENTRANT_FUNC_NAMES=yes).
+ *	Compile and run src/tools/test_thread_funcs.c to see if your operating
+ *	system requires reentrant function names.
  */
  
 
diff --git a/src/tools/test_thread_funcs.c b/src/tools/test_thread_funcs.c
new file mode 100644
index 0000000000000000000000000000000000000000..6661f5e867141e1dff0ffc2693f4061baf7ef58a
--- /dev/null
+++ b/src/tools/test_thread_funcs.c
@@ -0,0 +1,126 @@
+/*-------------------------------------------------------------------------
+ *
+ * test_thread_funcs.c
+ *      libc thread test program
+ *
+ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *	$Header: /cvsroot/pgsql/src/tools/Attic/test_thread_funcs.c,v 1.1 2003/09/03 19:30:31 momjian Exp $
+ *
+ *	This program tests to see if your standard libc functions use
+ *	pthread_setspecific()/pthread_getspecific() to be thread-safe.
+ *	See src/port/thread.c for more details.
+ *
+ *	This program first tests to see if each function returns a constant
+ *	memory pointer within the same thread, then, assuming it does, tests
+ *	to see if the pointers are different for different threads.  If they
+ *	are, the function is thread-safe.
+ *
+ *	This program must be compiled with the thread flags required by your
+ *	operating system.  See src/template for the appropriate flags, if any.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+
+#include <pthread.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <netdb.h>
+#include <sys/types.h>
+#include <pwd.h>
+#include <string.h>
+#include <errno.h>
+
+void func_call_1(void);
+void func_call_2(void);
+
+struct hostent *hostent_p1;
+struct hostent *hostent_p2;
+
+struct passwd *passwd_p1;
+struct passwd *passwd_p2;
+
+char *strerror_p1;
+char *strerror_p2;
+
+int main(int argc, char *argv[])
+{
+	pthread_t		thread1,
+					thread2;
+
+	if (argc > 1)
+	{
+			fprintf(stderr, "Usage: %s\n", argv[0]);
+			return 1;
+	}
+
+	pthread_create(&thread1, NULL, (void *) func_call_1, NULL);
+	pthread_create(&thread2, NULL, (void *) func_call_2, NULL);
+	pthread_join(thread1, NULL);
+	pthread_join(thread2, NULL);
+
+	if (hostent_p1 != hostent_p2 &&
+		passwd_p1 != passwd_p2 &&
+		strerror_p1 != strerror_p2)
+		printf("Your functions are all thread-safe\n");
+	else
+		printf("Your functions are _not_ all thread-safe\n");
+
+	return 0;
+}
+
+void func_call_1(void) {
+	void *p;
+
+	hostent_p1 = gethostbyname("yahoo.com");
+	p = gethostbyname("slashdot.org");
+	if (hostent_p1 != p)
+	{
+		printf("Your gethostbyname() changes the static memory area between calls\n");
+		hostent_p1 = NULL;	/* force thread-safe failure report */
+	}
+
+	passwd_p1 = getpwuid(0);
+	p = getpwuid(1);
+	if (passwd_p1 != p)
+	{
+		printf("Your getpwuid() changes the static memory area between calls\n");
+		passwd_p1 = NULL;	/* force thread-safe failure report */
+	}
+
+	strerror_p1 = strerror(EACCES);
+	/*
+	 *	If strerror() uses sys_errlist, the pointer might change for different
+	 *	errno values, so we don't check to see if it varies within the thread.
+	 */
+}
+
+
+void func_call_2(void) {
+	void *p;
+
+	hostent_p2 = gethostbyname("google.com");
+	p = gethostbyname("postgresql.org");
+	if (hostent_p2 != p)
+	{
+		printf("Your gethostbyname() changes the static memory area between calls\n");
+		hostent_p2 = NULL;	/* force thread-safe failure report */
+	}
+
+	passwd_p2 = getpwuid(2);
+	p = getpwuid(3);
+	if (passwd_p2 != p)
+	{
+		printf("Your getpwuid() changes the static memory area between calls\n");
+		passwd_p2 = NULL;	/* force thread-safe failure report */
+	}
+
+	strerror_p2 = strerror(EINVAL);
+	/*
+	 *	If strerror() uses sys_errlist, the pointer might change for different
+	 *	errno values, so we don't check to see if it varies within the thread.
+	 */
+}