1990-12-19 13:51:23 +01:00
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GDB Internals documentation
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1990-12-13 16:49:06 +01:00
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1990-12-19 13:51:23 +01:00
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This needs to be wrapped in texinfo stuff...
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Cleanups
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Cleanups are a structured way to deal with things that need to be done
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later. When your code does something (like malloc some memory, or open
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a file) that needs to be undone later (e.g. free the memory or close
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the file), it can make a cleanup. The cleanup will be done at some
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future point: when the command is finished, when an error occurs, or
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when your code decides it's time to do cleanups.
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You can also discard cleanups, that is, throw them away without doing
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what they say. This is only done if you ask that it be done.
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Syntax:
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old_chain = make_cleanup (function, arg);
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This makes a cleanup which will cause FUNCTION to be called with ARG
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(a char *) later. The result, OLD_CHAIN, is a handle that can be
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passed to do_cleanups or discard_cleanups later. Unless you are
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going to call do_cleanups or discard_cleanups yourself,
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you can ignore the result from make_cleanup.
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do_cleanups (old_chain);
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Performs all cleanups done since make_cleanup returned OLD_CHAIN.
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E.g.: make_cleanup (a, 0); old = make_cleanup (b, 0); do_cleanups (old);
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will call b() but will not call a(). The cleanup that calls a() will remain
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in the cleanup chain, and will be done later unless otherwise discarded.
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discard_cleanups (old_chain);
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Same as do_cleanups except that it just removes the cleanups from the
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chain and does not call the specified functions.
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Some functions, e.g. fputs_filtered() or error(), specify that they
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"should not be called when cleanups are not in place". This means
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that any actions you need to reverse in the case of an error or
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interruption must be on the cleanup chain before you call these functions,
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since they might never return to your code (they "longjmp" instead).
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