Messages in this thread | | | From | Herbert Xu <> | Subject | Re: [2.6 patch] drivers/net/smc-mca.c: cleanups | Date | Sun, 20 Feb 2005 21:37:32 +1100 |
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Arjan van de Ven <arjan@infradead.org> wrote: > >> I've used this technique in a few very >> small programs to reduce their size (I could strip off both their bss and >> data sections to save space). Also, I believe that the compiler is able >> to optimize code using consts, but this is pure speculation, I've not >> verified it. > > Afaik that's the main difference between C and C++; in C you can still > change "const" variables... in C++ thats illegal (at least that's what I > remember and google seems to support somewhat ;)
The compiler does use the const modifier on a static object to optimise code. Try compiling this program:
const int x;
int bar(int);
int foo(void) { bar(x); return bar(x); }
With the const gcc (3.3.4) will only load x once while it'll reload it after calling bar if you remove the const modifier. -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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