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Don't worry about preprocessor when testing long long.

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See: http://lists.gnu.org/archive/html/bug-gnulib/2007-11/msg00075.html
* doc/autoconf.texi (Preprocessor Arithmetic): New section.
(AC_TYPE_LONG_LONG_INT, AC_TYPE_UNSIGNED_LONG_LONG_INT):
These no longer check for preprocessor flaws.
* lib/autoconf/types.m4 (_AC_TYPE_LONG_LONG_SNIPPET):
Do not check for preprocessor flows.
This commit is contained in:
Paul Eggert 2007-11-13 00:16:19 -08:00
parent 48520ed2f7
commit 9b0314cc93
3 changed files with 35 additions and 16 deletions
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10
ChangeLog
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@ -1,3 +1,13 @@
2007-11-13 Paul Eggert <eggert@cs.ucla.edu>
Don't worry about preprocessor when testing long long.
See: http://lists.gnu.org/archive/html/bug-gnulib/2007-11/msg00075.html
* doc/autoconf.texi (Preprocessor Arithmetic): New section.
(AC_TYPE_LONG_LONG_INT, AC_TYPE_UNSIGNED_LONG_LONG_INT):
These no longer check for preprocessor flaws.
* lib/autoconf/types.m4 (_AC_TYPE_LONG_LONG_SNIPPET):
Do not check for preprocessor flows.
2007-11-13 Jim Meyering <meyering@redhat.com>
Adapt dependencies, now that a version change doesn't modify configure.ac

32
doc/autoconf.texi
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@ -518,6 +518,7 @@ Portable C and C++ Programming
* Varieties of Unportability:: How to make your programs unportable
* Integer Overflow:: When integers get too large
* Preprocessor Arithmetic:: @code{#if} expression problems
* Null Pointers:: Properties of null pointers
* Buffer Overruns:: Subscript errors and the like
* Volatile Objects:: @code{volatile} and signals
@ -6123,8 +6124,10 @@ range or precision than the @code{double} type, define
@acindex{TYPE_LONG_LONG_INT}
@cvindex HAVE_LONG_LONG_INT
If the C compiler supports a working @code{long long int} type, define
@code{HAVE_LONG_LONG_INT}. This test also validates that the
preprocessor can handle integers with the @samp{LL} suffix.
@code{HAVE_LONG_LONG_INT}. However, this test does not test
@code{long long int} values in preprocessor @code{#if} expressions,
because too many compilers mishandle such expressions.
@xref{Preprocessor Arithmetic}.
@end defmac
@defmac AC_TYPE_MBSTATE_T
@ -6261,12 +6264,10 @@ exists.
@acindex{TYPE_UNSIGNED_LONG_LONG_INT}
@cvindex HAVE_UNSIGNED_LONG_LONG_INT
If the C compiler supports a working @code{unsigned long long int} type,
define @code{HAVE_UNSIGNED_LONG_LONG_INT}. This test also validates
that the preprocessor can handle integers with the @samp{ULL} suffix.
However, portable code cannot mix @code{unsigned long int} and
@code{unsigned long long int} types in preprocessor expressions,
since the @acronym{HP-UX} 11.00 preprocessor does not use consistent
promotion rules.
define @code{HAVE_UNSIGNED_LONG_LONG_INT}. However, this test does not test
@code{unsigned long long int} values in preprocessor @code{#if} expressions,
because too many compilers mishandle such expressions.
@xref{Preprocessor Arithmetic}.
@end defmac
@node Generic Types
@ -16291,6 +16292,7 @@ more information.
@menu
* Varieties of Unportability:: How to make your programs unportable
* Integer Overflow:: When integers get too large
* Preprocessor Arithmetic:: @code{#if} expression problems
* Null Pointers:: Properties of null pointers
* Buffer Overruns:: Subscript errors and the like
* Volatile Objects:: @code{volatile} and signals
@ -16656,6 +16658,20 @@ of these two values typically yields the same signal on these CPUs,
even though the C standard requires @code{INT_MIN % -1} to yield zero
because the expression does not overflow.
@node Preprocessor Arithmetic
@section Preprocessor Arithmetic
@cindex preprocessor arithmetic
In C99, preprocessor arithmetic, used for @code{#if} expressions, must
be evaluated as if all signed values are of type @code{intmax_t} and all
unsigned values of type @code{uintmax_t}. Many compilers are buggy in
this area, though. For example, as of 2007, Sun C mishandles @code{#if
LLONG_MIN < 0} on a platform with 32-bit @code{long int} and 64-bit
@code{long long int}. Also, some older preprocessors mishandle
constants ending in @code{LL}. To work around these problems, you can
compute the value of expressions like @code{LONG_MAX < LLONG_MAX} at
@code{configure}-time rather than at @code{#if}-time.
@node Null Pointers
@section Properties of Null Pointers
@cindex null pointers

9
lib/autoconf/types.m4
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@ -475,14 +475,7 @@ You should use `AC_TYPE_LONG_DOUBLE' or `AC_TYPE_LONG_DOUBLE_WIDER' instead.]
AC_DEFUN([_AC_TYPE_LONG_LONG_SNIPPET],
[
AC_LANG_PROGRAM(
[[/* Test preprocessor. */
#if ! (-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
error in preprocessor;
#endif
#if ! (18446744073709551615ULL <= -1ull)
error in preprocessor;
#endif
/* Test literals. */
[[/* Test literals. */
long long int ll = 9223372036854775807ll;
long long int nll = -9223372036854775807LL;
unsigned long long int ull = 18446744073709551615ULL;