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-rw-r--r--gcc/ada/a-ststio.adb30
1 files changed, 24 insertions, 6 deletions
diff --git a/gcc/ada/a-ststio.adb b/gcc/ada/a-ststio.adb
index 74c9be2da3c..8df6a379ba9 100644
--- a/gcc/ada/a-ststio.adb
+++ b/gcc/ada/a-ststio.adb
@@ -6,7 +6,7 @@
-- --
-- B o d y --
-- --
--- Copyright (C) 1992-2001, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2003, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
@@ -114,11 +114,14 @@ package body Ada.Streams.Stream_IO is
Name : in String := "";
Form : in String := "")
is
- File_Control_Block : Stream_AFCB;
+ Dummy_File_Control_Block : Stream_AFCB;
+ pragma Warnings (Off, Dummy_File_Control_Block);
+ -- Yes, we know this is never assigned a value, only the tag
+ -- is used for dispatching purposes, so that's expected.
begin
FIO.Open (File_Ptr => AP (File),
- Dummy_FCB => File_Control_Block,
+ Dummy_FCB => Dummy_File_Control_Block,
Mode => To_FCB (Mode),
Name => Name,
Form => Form,
@@ -212,11 +215,14 @@ package body Ada.Streams.Stream_IO is
Name : in String;
Form : in String := "")
is
- File_Control_Block : Stream_AFCB;
+ Dummy_File_Control_Block : Stream_AFCB;
+ pragma Warnings (Off, Dummy_File_Control_Block);
+ -- Yes, we know this is never assigned a value, only the tag
+ -- is used for dispatching purposes, so that's expected.
begin
FIO.Open (File_Ptr => AP (File),
- Dummy_FCB => File_Control_Block,
+ Dummy_FCB => Dummy_File_Control_Block,
Mode => To_FCB (Mode),
Name => Name,
Form => Form,
@@ -228,7 +234,19 @@ package body Ada.Streams.Stream_IO is
Reset (File, Mode);
- File.Last_Op := Op_Read;
+ -- Set last operation. The purpose here is to ensure proper handling
+ -- of the initial operation. In general, a write after a read requires
+ -- resetting and doing a seek, so we set the last operation as Read
+ -- for an In_Out file, but for an Out file we set the last operation
+ -- to Op_Write, since in this case it is not necessary to do a seek
+ -- (and furthermore there are situations (such as the case of writing
+ -- a sequential Posix FIFO file) where the lseek would cause problems.
+
+ if Mode = Out_File then
+ File.Last_Op := Op_Write;
+ else
+ File.Last_Op := Op_Read;
+ end if;
end Open;
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