On Thu, Aug 05, 2010 at 07:02:06PM +0800, Changli Gao wrote: > > the second parameter of strlcpy() must a NUL terminated C string. I > think you means strncpy(). > Both strncpy() and strlcpy() take a limitter. The difference is that strlcpy() always takes on a terminator and strncpy() only adds a terminator if there is space. strlcpy() is a BSD function that never caught on in Linux. The glibc maintainers think that if you accidentally chop off the last part of a word that makes you an idiot. They think you should known the length of your data at all times and use memcpy() or a proper string library. I prefer strlcpy() to strncpy(). Some people do stuff like: strncpy(bar, foo, n); bar[n] = '\0'; You have to read through the code to find if n is "sizeof(bar)" or "sizeof(bar) - 1". Which is a pain in the arse. strlcpy() is explicit and it's just one line of code instead of two. The other tricky thing you should remember about strncpy() is that the posix version writes NUL chars from the end of the string to the limitter but the kernel version only copies one NUL character. regards, dan carpenter > FYI: > http://lxr.linux.no/#linux+v2.6.35/lib/string.c#L146 > http://lxr.linux.no/#linux+v2.6.35/lib/string.c#L119 > -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
