Re: [RFC] New kernel-message logging API (take 2)

From: Dick Streefland
Date: Fri Sep 28 2007 - 04:23:12 EST

"Vegard Nossum" <vegard.nossum@xxxxxxxxx> wrote:
| It should be possible to optimize out multi-line (block) entries
| based on log-level filtering even though the log-level is only given
| in the first call (the initializer). It may take the shape of an
| if-block that spans several macros. This is not very elegant or robust
| if the macros are used incorrectly, however. Aborting a message can
| also be hard this way (since the abort would usually appear inside an
| if-statement that tests for some abnormal condition, thus appear in a
| different block, and thoroughly mess up the bracket order).
| Example: {
| #define kprint_block_init(block, loglevel) \
| if(loglevel > CONFIG_KPRINT_LOGLEVEL_MAX) { \
| kprint_real_block_init(block, loglevel);
| #define kprint_block(block, fmt, ...) \
| kprint_real_block(block, fmt, ## __VA_ARGS__);
| #define kprint_block_flush(block) \
| kprint_real_block_flush(block); \
| }

As you point out yourself, this is not very elegant or robust. In fact,
it is very dangerous. Why not simply pass the loglevel to each macro?

Dick Streefland //// Altium BV
dick.streefland@xxxxxxxxx (@ @)

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