Re: [bug-gnulib] FYI: comment nits in intprops.h

[Paul Eggert]

Jim Meyering <address@hidden> writes:

> 2005-03-26  Jim Meyering  <address@hidden>
>
>       Comment nits.
>       * intprops.h: Add the apostrophe in `(one|two)'s complement'.
>       Correct typos: s/or/of/.

Thanks for picking that up.  However, I just checked Knuth Volume 2
(3rd edition, section 4.1, pages 203-204), and the correct spelling is
"ones' complement".  The idea is that "two's complement" complements
with respect to a single power of 2; "ones' complement" complements
with respect to 111111....1, so it uses the plural possessive.  I
never could remember this detail, which is why I sometimes lazily
omitted the apostrophe.  Knuth goes on to describe "twos' complement",
which is base 3 and complements with respect to 22222....2.  (I guess
I'll remember this stuff better now.  :-)

Also, the /or/of/ fix isn't quite right, since the comment was
intended to say that the argument can be either a type or an
expression yielding a value of a type.  And the patches should be
propogated to the glibc files.

So I installed the following:

2005-03-26  Paul Eggert  <address@hidden>

        * intprops.h:
        "one's complement" -> "ones' complement" in comment, as per Knuth.
        "value of type" -> "type or expression" in comment.
        * mktime.c, strftime.c: Propagate intprops.h comment nits.

Index: lib/intprops.h
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/intprops.h,v
retrieving revision 1.3
retrieving revision 1.5
diff -p -u -r1.3 -r1.5
--- lib/intprops.h      26 Mar 2005 11:10:52 -0000      1.3
+++ lib/intprops.h      26 Mar 2005 17:53:44 -0000      1.5
@@ -28,7 +28,7 @@
 #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
 
 /* True if negative values of the signed integer type T use two's
-   complement, one's complement, or signed magnitude representation,
+   complement, ones' complement, or signed magnitude representation,
    respectively.  Much GNU code assumes two's complement, but some
    people like to be portable to all possible C hosts.  */
 #define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
@@ -53,13 +53,13 @@
        ? (t) -1 \
        : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
 
-/* Bound on length of the string representing an integer value of type T.
+/* Bound on length of the string representing an integer type or expression T.
    Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485;
    add 1 for integer division truncation; add 1 more for a minus sign
    if needed.  */
 #define INT_STRLEN_BOUND(t) \
   ((sizeof (t) * CHAR_BIT - 1) * 146 / 485 + 2)
 
-/* Bound on buffer size needed to represent an integer value of type T,
+/* Bound on buffer size needed to represent an integer type or expression T,
    including the terminating null.  */
 #define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
Index: lib/mktime.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/mktime.c,v
retrieving revision 1.49
retrieving revision 1.50
diff -p -u -r1.49 -r1.50
--- lib/mktime.c        15 Mar 2005 00:39:17 -0000      1.49
+++ lib/mktime.c        26 Mar 2005 18:08:56 -0000      1.50
@@ -68,9 +68,9 @@
    an integer.  */
 #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
 
-/* True if negative values of the signed integer type T use twos
-   complement, ones complement, or signed magnitude representation,
-   respectively.  Much GNU code assumes twos complement, but some
+/* True if negative values of the signed integer type T use two's
+   complement, ones' complement, or signed magnitude representation,
+   respectively.  Much GNU code assumes two's complement, but some
    people like to be portable to all possible C hosts.  */
 #define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
 #define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
Index: lib/strftime.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/strftime.c,v
retrieving revision 1.81
retrieving revision 1.82
diff -p -u -r1.81 -r1.82
--- lib/strftime.c      19 Mar 2005 05:34:28 -0000      1.81
+++ lib/strftime.c      26 Mar 2005 18:08:56 -0000      1.82
@@ -120,7 +120,7 @@ extern char *tzname[];
    ? (a) >> (b)                \
    : (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))
 
-/* Bound on length of the string representing an integer value or type T.
+/* Bound on length of the string representing an integer type or expression T.
    Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485;
    add 1 for integer division truncation; add 1 more for a minus sign
    if needed.  */