33 lines
1.5 KiB
Text
33 lines
1.5 KiB
Text
Some examples of ready-to-dynamic-load builtins. Most of the
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examples given are reimplementations of standard commands whose
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execution time is dominated by process startup time. The
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exceptions are sleep, which allows you to sleep for fractions
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of a second, finfo, which provides access to the rest of the
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elements of the `stat' structure that `test' doesn't let you
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see, and pushd/popd/dirs, which allows you to compile them out
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of the shell.
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All of the new builtins in ksh93 that bash didn't already have
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are included here, as is the ksh `print' builtin.
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The configure script in the top-level source directory uses the
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support/shobj-conf script to set the right values in the Makefile,
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so you should not need to change the Makefile. If your system
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is not supported by support/shobj-conf, and it has the necessary
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facilities for building shared objects and support for the
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dlopen/dlsyn/dlclose/dlerror family of functions, please make
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the necessary changes to support/shobj-conf and send the changes
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to bash-maintainers@gnu.org.
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Loadable builtins are loaded into a running shell with
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enable -f filename builtin-name
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enable uses a simple reference-counting scheme to avoid unloading a
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shared object that implements more than one loadable builtin before
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all loadable builtins implemented in the object are removed.
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Many of the details needed by builtin writers are found in hello.c,
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the canonical example. There is no real `builtin writers' programming
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guide'. The file template.c provides a template to use for creating
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new loadable builtins.
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