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    SubjectRe: Use enum to declare errno values
    Date
    On Thursday 01 December 2005 22:01, linux-os (Dick Johnson) wrote:
    > On Thu, 24 Nov 2005, Paul Jackson wrote:
    >
    > > If errno's were an enum type, what would be the type
    > > of the return value of a variety of kernel routines
    > > that now return an int, returning negative errno's on
    > > error and zero or positive values on success?
    >
    > enums are 'integer types', one of the reasons why #defines
    > which are also 'integer types' are just as useful. If you
    > want to auto-increment these integer types, then enums are
    > useful. Otherwise, just use definitions.

    There is another reason why enums are better than #defines:

    file.h:
    #define foo 123
    enum {
    bar = 123
    };


    file.c:
    ...
    #include "something_which_eventually_includes_file.h"
    ...
    int f(int foo, int bar)
    {
    return foo+bar;
    }

    Above program has compile-time bug, but it's rather hard
    to see it if you are looking at file.c alone.
    --
    vda
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