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Re: Comparing binary files with Diff 3.2 compiled with MinGW
From: |
Bruno Haible |
Subject: |
Re: Comparing binary files with Diff 3.2 compiled with MinGW |
Date: |
Sun, 13 May 2012 22:58:23 +0200 |
User-agent: |
KMail/4.7.4 (Linux/3.1.10-1.9-desktop; KDE/4.7.4; x86_64; ; ) |
Paul Eggert wrote:
> With that approach, code like this:
>
> set_binary_mode (current->desc, prev_mode);
>
> yields the following undesirable diagnostic:
>
> io.c:127:8: error: statement with no effect [-Werror=unused-value]
>
> How about something like the following definition instead?
> It would also have the advantage of better type-checking on
> POSIX hosts.
>
> static int
> set_binary_mode (int fd, int mode)
> {
> (void) fd;
> (void) mode;
> return O_BINARY;
> }
OK. Since I don't want all callers to use '(void)' casts, I'm making it
a function, like you say. An inline function, since I don't like to penalize
the compiled code on GNU systems for such no-ops.
Bruno
2012-05-13 Bruno Haible <address@hidden>
Paul Eggert <address@hidden>
binary-io: Define set_binary_mode function.
* lib/binary-io.h (set_binary_mode): New function.
(SET_BINARY): Define in terms of set_binary_mode.
* modules/binary-io (configure.ac): Require AC_C_INLINE.
* tests/test-binary-io.c (main): Accept an argument, and test either
set_binary_mode or SET_BINARY depending on the argument.
* tests/test-binary-io.sh: Invoke test-binary-io twice, with an
argument. Clean up also t-bin-out0.tmp.
--- lib/binary-io.h.orig Sun May 13 22:54:11 2012
+++ lib/binary-io.h Sun May 13 22:51:50 2012
@@ -25,28 +25,41 @@
so we include it here first. */
#include <stdio.h>
-/* SET_BINARY (fd);
- changes the file descriptor fd to perform binary I/O. */
+/* set_binary_mode (fd, mode)
+ sets the binary/text I/O mode of file descriptor fd to the given mode
+ (must be O_BINARY or O_TEXT) and returns the previous mode. */
#if O_BINARY
# if defined __EMX__ || defined __DJGPP__ || defined __CYGWIN__
# include <io.h> /* declares setmode() */
+# define set_binary_mode setmode
# else
-# define setmode _setmode
+# define set_binary_mode _setmode
# undef fileno
# define fileno _fileno
# endif
-# ifdef __DJGPP__
-# include <unistd.h> /* declares isatty() */
- /* Avoid putting stdin/stdout in binary mode if it is connected to
- the console, because that would make it impossible for the user
- to interrupt the program through Ctrl-C or Ctrl-Break. */
-# define SET_BINARY(fd) ((void) (!isatty (fd) ? (setmode (fd, O_BINARY), 0) :
0))
-# else
-# define SET_BINARY(fd) ((void) setmode (fd, O_BINARY))
-# endif
#else
- /* On reasonable systems, binary I/O is the default. */
-# define SET_BINARY(fd) /* do nothing */ ((void) 0)
+ /* On reasonable systems, binary I/O is the only choice. */
+ /* Use an inline function rather than a macro, to avoid gcc warnings
+ "warning: statement with no effect". */
+static inline int
+set_binary_mode (int fd, int mode)
+{
+ (void) fd;
+ (void) mode;
+ return O_BINARY;
+}
+#endif
+
+/* SET_BINARY (fd);
+ changes the file descriptor fd to perform binary I/O. */
+#ifdef __DJGPP__
+# include <unistd.h> /* declares isatty() */
+ /* Avoid putting stdin/stdout in binary mode if it is connected to
+ the console, because that would make it impossible for the user
+ to interrupt the program through Ctrl-C or Ctrl-Break. */
+# define SET_BINARY(fd) ((void) (!isatty (fd) ? (set_binary_mode (fd,
O_BINARY), 0) : 0))
+#else
+# define SET_BINARY(fd) ((void) set_binary_mode (fd, O_BINARY))
#endif
#endif /* _BINARY_H */
--- modules/binary-io.orig Sun May 13 22:54:11 2012
+++ modules/binary-io Sun May 13 22:47:52 2012
@@ -8,6 +8,7 @@
fcntl-h
configure.ac:
+AC_REQUIRE([AC_C_INLINE])
Makefile.am:
lib_SOURCES += binary-io.h
--- tests/test-binary-io.c.orig Sun May 13 22:54:12 2012
+++ tests/test-binary-io.c Sun May 13 03:56:50 2012
@@ -30,26 +30,40 @@
#include "macros.h"
int
-main ()
+main (int argc, char *argv[])
{
/* Test the O_BINARY macro. */
{
int fd =
- open ("t-bin-out2.tmp", O_CREAT | O_TRUNC | O_RDWR | O_BINARY, 0600);
+ open ("t-bin-out0.tmp", O_CREAT | O_TRUNC | O_RDWR | O_BINARY, 0600);
if (write (fd, "Hello\n", 6) < 0)
exit (1);
close (fd);
}
{
struct stat statbuf;
- if (stat ("t-bin-out2.tmp", &statbuf) < 0)
+ if (stat ("t-bin-out0.tmp", &statbuf) < 0)
exit (1);
ASSERT (statbuf.st_size == 6);
}
- /* Test the SET_BINARY macro. */
- SET_BINARY (1);
- fputs ("Hello\n", stdout);
+ switch (argv[1][0])
+ {
+ case '1':
+ /* Test the set_binary_mode() function. */
+ set_binary_mode (1, O_BINARY);
+ fputs ("Hello\n", stdout);
+ break;
+
+ case '2':
+ /* Test the SET_BINARY macro. */
+ SET_BINARY (1);
+ fputs ("Hello\n", stdout);
+ break;
+
+ default:
+ break;
+ }
return 0;
}
--- tests/test-binary-io.sh.orig Sun May 13 22:54:12 2012
+++ tests/test-binary-io.sh Sat May 12 22:28:28 2012
@@ -3,9 +3,11 @@
tmpfiles=""
trap 'rm -fr $tmpfiles' 1 2 3 15
-tmpfiles="$tmpfiles t-bin-out1.tmp t-bin-out2.tmp"
-./test-binary-io${EXEEXT} > t-bin-out1.tmp || exit 1
-cmp t-bin-out1.tmp t-bin-out2.tmp > /dev/null || exit 1
+tmpfiles="$tmpfiles t-bin-out0.tmp t-bin-out1.tmp t-bin-out2.tmp"
+./test-binary-io${EXEEXT} 1 > t-bin-out1.tmp || exit 1
+cmp t-bin-out0.tmp t-bin-out1.tmp > /dev/null || exit 1
+./test-binary-io${EXEEXT} 2 > t-bin-out2.tmp || exit 1
+cmp t-bin-out0.tmp t-bin-out2.tmp > /dev/null || exit 1
rm -fr $tmpfiles
- Re: Comparing binary files with Diff 3.2 compiled with MinGW, (continued)
Re: Comparing binary files with Diff 3.2 compiled with MinGW, Paul Eggert, 2012/05/12
Re: Comparing binary files with Diff 3.2 compiled with MinGW, Paul Eggert, 2012/05/13
Re: Comparing binary files with Diff 3.2 compiled with MinGW,
Bruno Haible <=
Re: Comparing binary files with Diff 3.2 compiled with MinGW, Eric Blake, 2012/05/14