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On Monday 15 May 2006 15:26, Duncan wrote: |
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> Paul de Vrieze <pauldv@g.o> posted |
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> 200605151313.22900.pauldv@g.o, excerpted below, on Mon, 15 May |
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> |
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> 2006 13:13:16 +0200: |
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> > Actually this is only one part of the problem. Another part is caused |
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> > by the fact that in general C++ programs (specially the kde/qt ones) |
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> > include megabytes of header files. |
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> |
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> That reminds me... What ever happened to the precompiled headers thing? |
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> Could it be useful for Gentoo? (I remember reading about how great |
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> precompiled headers were going to be, but not fully understanding the |
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> implications, and I haven't the foggiest if gcc ever got the feature.) |
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|
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Well, packages within gentoo could support it. It is necessary to have |
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support for it in the package though. The catch with the headers is that |
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only one header in a compilation can be used precompiled. Effectively |
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this implies the following system: |
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1 big include most stuff header. |
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Each c file first includes that header |
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Then includes others. |
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The big include header is precompiled. |
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Speedup is achieved. |
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|
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This means that it has consequences for the code. That makes it harder to |
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use. And impossible for gentoo to enforce it. It is one of the |
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consequences of the usage of includes (instead of proper modules) by C. |
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|
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Be aware the choice for include files and a separate preprocessor made a |
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lot of sense when C was designed. C++ has them for compatibility, but for |
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any new language splitting headers and body in different files no longer |
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makes sense. |
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|
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Paul |
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|
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-- |
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Paul de Vrieze |
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Gentoo Developer |
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Mail: pauldv@g.o |
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Homepage: http://www.devrieze.net |
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