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Diffstat (limited to 'doc/src/sgml/pltcl.sgml')
| -rw-r--r-- | doc/src/sgml/pltcl.sgml | 43 |
1 files changed, 24 insertions, 19 deletions
diff --git a/doc/src/sgml/pltcl.sgml b/doc/src/sgml/pltcl.sgml index 3ffaf81fe5e..d4bdabeeaed 100644 --- a/doc/src/sgml/pltcl.sgml +++ b/doc/src/sgml/pltcl.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/pltcl.sgml,v 2.40 2006/05/27 20:24:16 adunstan Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/pltcl.sgml,v 2.41 2006/05/30 11:40:21 momjian Exp $ --> <chapter id="pltcl"> <title>PL/Tcl - Tcl Procedural Language</title> @@ -25,22 +25,27 @@ <title>Overview</title> <para> - PL/Tcl offers most of the capabilities a function - writer has in the C language, except for some restrictions. + PL/Tcl offers most of the capabilities a function writer has in + the C language, with a few restrictions, and with the addition of + the powerful string processing libraries that are available for + Tcl. </para> <para> - The good restriction is that everything is executed in a safe - Tcl interpreter. In addition to the limited command set of safe Tcl, only - a few commands are available to access the database via SPI and to raise - messages via <function>elog()</>. There is no way to access internals of the - database server or to gain OS-level access under the permissions of the - <productname>PostgreSQL</productname> server process, as a C function can do. - Thus, any unprivileged database user may be - permitted to use this language. + One compelling <emphasis>good</emphasis> restriction is that + everything is executed from within the safety of the context of a + Tcl interpreter. In addition to the limited command set of safe + Tcl, only a few commands are available to access the database via + SPI and to raise messages via <function>elog()</>. PL/Tcl + provides no way to access internals of the database server or to + gain OS-level access under the permissions of the + <productname>PostgreSQL</productname> server process, as a C + function can do. Thus, unprivileged database users may be trusted + to use this language; it does not give them unlimited authority. </para> <para> - The other, implementation restriction is that Tcl functions cannot - be used to create input/output functions for new data types. + The other notable implementation restriction is that Tcl functions + may not be used to create input/output functions for new data + types. </para> <para> Sometimes it is desirable to write Tcl functions that are not restricted @@ -55,12 +60,12 @@ a user logged in as the database administrator. </para> <para> - The shared object for the <application>PL/Tcl</> and <application>PL/TclU</> call handlers is - automatically built and installed in the - <productname>PostgreSQL</productname> - library directory if Tcl support is specified - in the configuration step of the installation procedure. To install - <application>PL/Tcl</> and/or <application>PL/TclU</> in a particular database, use the + The shared object code for the <application>PL/Tcl</> and + <application>PL/TclU</> call handlers is automatically built and + installed in the <productname>PostgreSQL</productname> library + directory if Tcl support is specified in the configuration step of + the installation procedure. To install <application>PL/Tcl</> + and/or <application>PL/TclU</> in a particular database, use the <command>createlang</command> program, for example <literal>createlang pltcl <replaceable>dbname</></literal> or <literal>createlang pltclu <replaceable>dbname</></literal>. |