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diff --git a/PLUGINS.html b/PLUGINS.html index 4f8a70ed..bbe1a1de 100644 --- a/PLUGINS.html +++ b/PLUGINS.html @@ -183,6 +183,40 @@ its memory. You don't need to worry about the details behind all this. <p> If your plugin requires additional source files, simply add them to your plugin's source directory and adjust the <tt>Makefile</tt> accordingly. +<p> +<!--X1.1.1--><table width=100%><tr><td bgcolor=red> </td><td width=100%> +Header files usually contain preprocessor statements that prevent the same +file (or rather its contents, to be precise) from being included more than once, like + +<p><table><tr><td bgcolor=#F0F0F0><pre><br> +#ifndef __I18N_H +#define __I18N_H + +... + +#endif //__I18N_H +</pre></td></tr></table><p> + +The example shown here is the way VDR does this in its core source files. +It takes the header file's name, converts it to all uppercase, replaces the +dot with an underline and preceedes the whole thing with two underlines. +The GNU library header files do this pretty much the same way, except that they +usually precede the name with only one underline (there are exceptions, though). +<p> +As long as you make shure that none of your plugin's header files will be named +like one of VDR's header files, you can use the same method as VDR. However, +if you want to name a header file like one that is already existing in VDR's +source (<tt>i18n.h</tt> would be a possible candidate for this), you may want +to make sure that the macros used here don't clash. How you do this is completely +up to you. You could, for instance, prepend the macro with a <tt>'P'</tt>, as in +<tt>P__I18N_H</tt>, or leave out the trailing <tt>_H</tt>, as in <tt>__I18N</tt>, +or use a completely different way to make sure a header file is included only once. +<p> +The 'hello' example that comes with VDR makes use of <a href="#Internationalization">internationalization</a> +and implements a file named <tt>i18n.h</tt>. To make sure it won't clash with VDR's +<tt>i18n.h</tt> it uses the macro <tt>_I18N__H</tt> (one underline at the beginning +and two replacing the dot). +<!--X1.1.1--></td></tr></table> <hr><h2>Construction and Destruction</h2> |