Commit6e3e600

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Update C comments to mention SQL:2003 handling of power return values.

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Lines changed: 3 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.155 2008/04/21 00:26:45 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.156 2008/05/09 15:36:06 momjian Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -1331,7 +1331,8 @@ dpow(PG_FUNCTION_ARGS)`
`1331`	`1331`
`1332`	`1332`	`/*`
`1333`	`1333`	`* The SQL spec requires that we emit a particular SQLSTATE error code for`
`1334`		`- * certain error conditions.`
	`1334`	`+ * certain error conditions. Specifically, we don't return a divide-by-zero`
	`1335`	`+ * error code for 0 ^ -1.`
`1335`	`1336`	`*/`
`1336`	`1337`	`if ((arg1==0&&arg2<0)\|\|`
`1337`	`1338`	`(arg1<0&&floor(arg2)!=arg2))`

Lines changed: 5 additions & 3 deletions

Original file line number	Diff line number	Diff line change
`@@ -14,7 +14,7 @@`
`14`	`14`	`* Copyright (c) 1998-2008, PostgreSQL Global Development Group`
`15`	`15`	`*`
`16`	`16`	`* IDENTIFICATION`
`17`		`- * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.112 2008/05/08 22:17:54 momjian Exp $`
	`17`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.113 2008/05/09 15:36:06 momjian Exp $`
`18`	`18`	`*`
`19`	`19`	`*-------------------------------------------------------------------------`
`20`	`20`	`*/`
`@@ -1893,8 +1893,9 @@ numeric_power(PG_FUNCTION_ARGS)`
`1893`	`1893`	`trunc_var(&arg2_trunc,0);`
`1894`	`1894`
`1895`	`1895`	`/*`
`1896`		`- * Return special SQLSTATE error codes for a few conditions mandated by`
`1897`		`- * the standard.`
	`1896`	`+ * The SQL spec requires that we emit a particular SQLSTATE error code for`
	`1897`	`+ * certain error conditions. Specifically, we don't return a divide-by-zero`
	`1898`	`+ * error code for 0 ^ -1.`
`1898`	`1899`	`*/`
`1899`	`1900`	`if ((cmp_var(&arg1,&const_zero)==0&&`
`1900`	`1901`	`cmp_var(&arg2,&const_zero)<0)\|\|`
`@@ -5283,6 +5284,7 @@ power_var_int(NumericVar base, int exp, NumericVar result, int rscale)`
`5283`	`5284`	`/*`
`5284`	`5285`	`*While 0 ^ 0 can be either 1 or indeterminate (error), we`
`5285`	`5286`	`*treat it as 1 because most programming languages do this.`
	`5287`	`+ *SQL:2003 also requires a return value of 1.`
`5286`	`5288`	`*http://en.wikipedia.org/wiki/Exponentiation#Zero_to_the_zero_power`
`5287`	`5289`	`*/`
`5288`	`5290`	`set_var_from_var(&const_one,result);`

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