Put back ERANGE test in dpow(). There are platforms that need this,

like my HPPA ...
This commit is contained in:
Tom Lane 2007-01-06 02:28:38 +00:00
parent 561b4bae78
commit b2965b9fce
1 changed files with 10 additions and 7 deletions

View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.142 2007/01/05 22:19:40 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.143 2007/01/06 02:28:38 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1442,24 +1442,27 @@ dpow(PG_FUNCTION_ARGS)
* pow() sets errno only on some platforms, depending on whether it
* follows _IEEE_, _POSIX_, _XOPEN_, or _SVID_, so we try to avoid
* using errno. However, some platform/CPU combinations return
* errno == EDOM and result == Nan, so we have to check for that and
* set result properly. For example, Linux on 32-bit x86 hardware
* returns EDOM/Nan for (-1) ^ 1e19, but (-1) ^ 1e18 returns
* 1 -- basically a negative base raised to a very high power causes
* it on some CPUs.
* errno == EDOM and result == Nan for negative arg1 and very large arg2
* (they must be using something different from our floor() test to
* decide it's invalid). Other platforms return errno == ERANGE and a
* large but finite result to signal overflow.
*/
errno = 0;
result = pow(arg1, arg2);
if (errno == EDOM && isnan(result))
{
if ((fabs(arg1) > 1 && arg2 >= 0) || (fabs(arg1) < 1 && arg2 < 0))
/* The sign if Inf is not significant in this case. */
/* The sign of Inf is not significant in this case. */
result = get_float8_infinity();
else if (fabs(arg1) != 1)
result = 0;
else
result = 1;
}
else if (errno == ERANGE)
{
result = (arg1 >= 0) ? get_float8_infinity() : -get_float8_infinity();
}
CHECKFLOATVAL(result, isinf(arg1) || isinf(arg2), arg1 == 0);
PG_RETURN_FLOAT8(result);