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Diffstat (limited to 'doc/gawk.texi')
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diff --git a/doc/gawk.texi b/doc/gawk.texi index 77f8b527..fca7cebb 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -845,6 +845,7 @@ particular records in a file and perform operations upon them. * Future Extensions:: New features that may be implemented one day. * Implementation Limitations:: Some limitations of the implementation. +* Old Extension Mechansim:: Some compatibility for old extensions. * Basic High Level:: The high level view. * Basic Data Typing:: A very quick intro to data types. @end detailmenu @@ -34303,6 +34304,7 @@ maintainers of @command{gawk}. Everything in it applies specifically to * Additions:: Making Additions To @command{gawk}. * Future Extensions:: New features that may be implemented one day. * Implementation Limitations:: Some limitations of the implementation. +* Old Extension Mechansim:: Some compatibility for old extensions. @end menu @node Compatibility Mode @@ -34933,6 +34935,42 @@ different limits. @item Size of a printf string @tab @code{MAX_INT } @end multitable +@node Old Extension Mechansim +@appendixsec Compatibility For Old Extensions + +@ref{Dynamic Extensions}, describes the supported API and mechanisms +for writing extensions for @command{gawk}. This API was introduced +in @strong{FIXME: VERSION}. However, for many years @command{gawk} +provided an extension mechanism that required knowledge of @command{gawk} +internals and that was not as well designed. + +In order to provide a transition period, @command{gawk} version +@strong{FIXME: VERSION} continues to support the original extension mechanism. +This will be true for the life of exactly one major release. This support +will be withdrawn, and removed from the source code, at the next major +release. + +Briefly, original-style extensions should be compiled by including the +@file{awk.h} header file in the extension source code. Additionally, +you must define the identifier @samp{GAWK} when building (use +@samp{-DGAWK} with Unix-style compilers). Otherwise, the definitions +in @file{gawkapi.h} will cause conflicts with those in @file{awk.h} +and your extension will not compile. + +Just as in previous versions, you load an old-style extension with the +@code{extension()} built-in function (which is not otherwise documented). +This function in turn finds and loads the shared object file containing +the extension and calls its @code{dl_load()} C routine. + +Because original-style and new-style extensions use different initialiation +routines (@code{dl_load()} versus @code{dlload()}), they may safely +be installed in the same directory (to be found by @env{AWKLIBPATH}) +without conflict. + +The @command{gawk} development team strongly recommends that you +convert any old extensions that you may have to use the new API +described in @ref{Dynamic Extensions}. + @c ENDOFRANGE impis @c ENDOFRANGE gawii |