[Ffmpeg-devel] [PATCH] video4linux2 input (original) (raw)

Måns Rullgård mru
Tue Feb 7 11:38:07 CET 2006

Erik Slagter said:

On Mon, 2006-02-06 at 12:06 -0500, Rich Felker wrote:

> To be even more elegant, I'd use a enum AND a table. #define's for > constants are evil, indeed.

Do you have any good reason to say this or is it just more CS dogma? Tables: less executable code -> less maintenance and bugs, if one entry works, all work.

Tables are good.

#defines: using #define for constants is reducing the C compiler to a super-assembler. If someone likes to program assembler, one should actually use the assembler and not misuse cpp for that purpose. C does have a notion of types (although not strongly enforced -- a shame) and using #defines you're totally defeating any sense of types. Also, if used heavily, the code is really difficult to debug, gcc -E output is not pretty.

Enums are treated exactly like ints. An enum type can be assigned any value, and any enum types are automatically converted to other integer types. There is one difference: some versions of gcc will warn if and enum is used in a switch statement, and there isn't a case for each value of the enum type or a default label. This warning is of questionable value, and ffmpeg explicitly disables it.

-- M?ns Rullg?rd mru at inprovide.com

More information about the ffmpeg-devel mailing list