How to zero a buffer
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How to zero a buffer
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Re: How to zero a buffer
#2This sort of thing would be exactly what should go into the "Friendly C" dialect being chatted about the other day--for things like zeroing memory, it's very unexpected that a compiler would be like "nah, not feeling it...nobody will notice anyways".
Re: How to zero a buffer
#3Can someone explain this line:
static void * (* const volatile memset_ptr)(void *, int, size_t) = memset;
Re: How to zero a buffer
#4Can someone explain this line: static void * (* const volatile memset_ptr)(void *, int, size_t) = memset; I've written some C but that is utter gibberish to me.
It declares a function pointer variable named "memset_ptr", and assigns the value of "memset" to it.
The "void *" before the first parenthesis is the return type of the function. The stuff in the first parenthesis applies to the function pointer variable. The second parenthesis lists the types of the arguments to memset.
Re: How to zero a buffer
#5For those of you unaware, Colin Percival (author of the blog) was for many years the FreeBSD Security Officer and he's highly recognized in the field for his expertise.
He also runs http://www.tarsnap.com/ which is arguably the most secure (and cost effective) back up solution in the market.
(I'm in no way affiliated with Colin and/or Tarsnap. Just a fan of his work and humble attitude.)
Re: How to zero a buffer
#6Can someone explain this line: static void * (* const volatile memset_ptr)(void *, int, size_t) = memset; I've written some C but that is utter gibberish to me.
memset_ptr is a const (we can't change its value) volatile (its value might change on its own) pointer to a function which taking three arguments (void * , int, size_t) and returning void *; and the memset_ptr symbol does not have external linkage and is initialized to "memset".
Re: How to zero a buffer
#7For those of you unaware, Colin Percival (author of the blog) was for many years the FreeBSD Security Officer and he's highly recognized in the field for his expertise. He also runs http://www.tarsnap.com/ which is arguably the most secure (and cost effective) back up solution in the market. (I'm in no way affiliated with Colin and/or Tarsnap. Just a fan of his work and humble attitude.)
humble attitude
I'm guessing you haven't seen the "comeback of all time" thread...
Re: How to zero a buffer
#8This sort of thing would be exactly what should go into the "Friendly C" dialect being chatted about the other day--for things like zeroing memory, it's very unexpected that a compiler would be like "nah, not feeling it...nobody will notice anyways".
If you're not worried about writing in a language which is widely supported, just use memset_s and tell people to find a C11 compiler.
Re: How to zero a buffer
#9Can someone explain this line: static void * (* const volatile memset_ptr)(void *, int, size_t) = memset; I've written some C but that is utter gibberish to me.
cdecl is really handy for stuff like this. Try it out:
http://cdecl.ridiculousfish.com/?q=static+void+*+%28*+const+...
Re: How to zero a buffer
#10Can someone explain this line: static void * (* const volatile memset_ptr)(void *, int, size_t) = memset; I've written some C but that is utter gibberish to me.
It's declaring a function pointer which is just an alias for memset and additionally qualifying it as volatile so the compiler doesn't optimize the call out.