Re: Comparing binary files with Diff 3.2 compiled with MinGW

[Bruno Haible]

Eli Zaretskii wrote:
>         * lib/binary-io.h [O_BINARY]: Include io.h on all systems that
>         have non-zero O_BINARY.

Not needed, see the other mail.

>         (O_TEXT) [!O_BINARY]: Define if not defined.

Why? You don't need it in the diffutils change. Additionally, gnulib's
<fcntl.h> already does it.

>         (setmode) [!O_BINARY]: Define to do nothing and return O_BINARY.

This part is basically OK, but lacks comments and a unit test.
Here's a proposed patch. It passes all tests on glibc, mingw, MSVC, Cygwin.


2012-05-12  Bruno Haible  <address@hidden>

        binary-io: Define setmode function.
        * lib/binary-io.h (setmode): Define if not defined by the platform.
        (SET_BINARY): Define in terms of setmode always.
        * tests/test-binary-io.c (main): Accept an argument, and test either
        setmode 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        Sat May 12 23:23:39 2012
+++ lib/binary-io.h     Sat May 12 22:23:04 2012
@@ -25,8 +25,9 @@
    so we include it here first.  */
 #include <stdio.h>
 
-/* SET_BINARY (fd);
-   changes the file descriptor fd to perform binary I/O.  */
+/* setmode (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() */
@@ -35,18 +36,21 @@
 #  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.  */
+# define setmode(fd, mode) ((void) (fd), (void) (mode), 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) ? (setmode (fd, O_BINARY), 0) : 
0))
+#else
+# define SET_BINARY(fd) ((void) setmode (fd, O_BINARY))
 #endif
 
 #endif /* _BINARY_H */
--- tests/test-binary-io.c.orig Sat May 12 23:23:39 2012
+++ tests/test-binary-io.c      Sat May 12 22:27:33 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 setmode() function.  */
+      setmode (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        Sat May 12 23:23:39 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