From 5e45211a64149b3c659b90ff2de6fa982a5a93ed Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 14:17:33 +0200 Subject: Adding upstream version 15.5. Signed-off-by: Daniel Baumann --- doc/src/sgml/html/xfunc-internal.html | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 doc/src/sgml/html/xfunc-internal.html (limited to 'doc/src/sgml/html/xfunc-internal.html') diff --git a/doc/src/sgml/html/xfunc-internal.html b/doc/src/sgml/html/xfunc-internal.html new file mode 100644 index 0000000..033ece2 --- /dev/null +++ b/doc/src/sgml/html/xfunc-internal.html @@ -0,0 +1,31 @@ + +38.9. Internal Functions
38.9. Internal Functions
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38.9. Internal Functions

+ Internal functions are functions written in C that have been statically + linked into the PostgreSQL server. + The “body” of the function definition + specifies the C-language name of the function, which need not be the + same as the name being declared for SQL use. + (For reasons of backward compatibility, an empty body + is accepted as meaning that the C-language function name is the + same as the SQL name.) +

+ Normally, all internal functions present in the + server are declared during the initialization of the database cluster + (see Section 19.2), + but a user could use CREATE FUNCTION + to create additional alias names for an internal function. + Internal functions are declared in CREATE FUNCTION + with language name internal. For instance, to + create an alias for the sqrt function: +

+CREATE FUNCTION square_root(double precision) RETURNS double precision
+    AS 'dsqrt'
+    LANGUAGE internal
+    STRICT;
+

+ (Most internal functions expect to be declared “strict”.) +

Note

+ Not all “predefined” functions are + “internal” in the above sense. Some predefined + functions are written in SQL. +

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38.8. Procedural Language Functions Home 38.10. C-Language Functions
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