Messages in this thread | | | Date | Tue, 9 Oct 2007 20:33:59 +0200 | From | Philipp Matthias Hahn <> | Subject | Re: [PATCH] NTFS error messages: replace static char pointers by static char arrays |
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Hello!
On Tue, Oct 09, 2007 at 02:40:35PM +0200, Ahmed S. Darwish wrote: > On Tue, Oct 09, 2007 at 01:55:42AM +0400, Dmitri Vorobiev wrote: > > The patch below contains a small code clean-up for the NTFS driver: all > > static char pointers to error message strings have been replaced by > > static char arrays.
char * a = "a"; // pointer and content can be changed const char * b = "b"; // the thing pointed to is const char * const c = "c"; // the pointer is const const char * const d = "d"; // pointer and content can't be changed
void foo(void) { *a = 'A'; a++; *b = 'B'; // error: assignment of read-only location b++; *c = 'C'; c++; // error: increment of read-only variable 'c' *d = 'D'; // error: assignment of read-only location d++; // error: increment of read-only variable 'd' }
> Isn't the only difference between char *c = "msg" and char c[] = "msg" is > that the first is a non-const pointer to a const char array while the second > is a modifiable char array ?
$ cat [ab].c const char *a = "a"; const char b[] = "b"; $ gcc -c [ab].c $ size [ab].o text data bss dec hex filename 2 4 0 6 6 a.o 2 0 0 2 2 b.o
'a' has two entries: one for the named read-writeable pointer, and one for the anonymous read-only string, the pointer points to. 'b' has a single entry: just the named read-only string.
BYtE Philipp -- / / (_)__ __ ____ __ Philipp Hahn / /__/ / _ \/ // /\ \/ / /____/_/_//_/\_,_/ /_/\_\ pmhahn@titan.lahn.de - 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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