From 86cc65a170b757aedfcc23f35cf02d3ed19f9bab Mon Sep 17 00:00:00 2001
From: Fergus Henderson <fjh@cs.mu.oz.au>
Date: Sat, 7 Feb 2004 12:44:18 +0000
Subject: [PATCH] Ensure that we don't update the timestamp on the ".mh" file
 if

Estimated hours taken: 0.5
Branches: main

compiler/export.m:
	Ensure that we don't update the timestamp on the ".mh" file if
	it hasn't changed, by writing it out to <modulename>.mh.tmp and
	then using "update_interface" to rename it to <modulename>.mh.
---
 compiler/export.m | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/compiler/export.m b/compiler/export.m
index 5d7361fcb..a79e57ddd 100644
--- a/compiler/export.m
+++ b/compiler/export.m
@@ -622,7 +622,7 @@ export__produce_header_file(ForeignExportDecls, ModuleName) -->
 			C_ExportDecls) },
 	{ HeaderExt = ".mh" },
 	module_name_to_file_name(ModuleName, HeaderExt, yes, FileName),
-	io__open_output(FileName, Result),
+	io__open_output(FileName ++ ".tmp", Result),
 	(
 		{ Result = ok(FileStream) }
 	->
@@ -670,13 +670,15 @@ export__produce_header_file(ForeignExportDecls, ModuleName) -->
 			"\n",
 			"#endif /* ", GuardMacroName, " */\n"]),
 		io__set_output_stream(OutputStream, _),
-		io__close_output(FileStream)
+		io__close_output(FileStream),
+		% rename "<ModuleName>.mh.tmp" to "<ModuleName>.mh".
+		update_interface(FileName)
 	;
 		io__progname_base("export.m", ProgName),
 		io__write_string("\n"),
 		io__write_string(ProgName),
 		io__write_string(": can't open `"),
-		io__write_string(FileName),
+		io__write_string(FileName ++ ".tmp"),
 		io__write_string("' for output\n"),
 		io__set_exit_status(1)
 	).