Re: preventing bad memory access
Re: preventing bad memory access
- Subject: Re: preventing bad memory access
- From: Wilker <email@hidden>
- Date: Thu, 20 Oct 2011 20:19:11 -0700
Thanks for the answers guys.
I mean I will use the f* operations.
But they are really safe? There is anything that I can do for extreme
situations in case to avoid bad memory access?
---
Wilker Lúcio
http://about.me/wilkerlucio/bio
Kajabi Consultant
+55 81 82556600
On Thu, Oct 20, 2011 at 12:09 AM, Don Quixote de la Mancha <
email@hidden> wrote:
> On Tue, Oct 18, 2011 at 9:22 AM, Jens Alfke <email@hidden> wrote:
> > On Oct 17, 2011, at 9:26 PM, Wilker wrote:
> > if the user is acessing a
> >> file from an external drive, and the file has 8gb, I only wanna read
> 64kb,
> >> so, I don't wanna read it all just for 64kb.
> >
> > Just use fopen/fseek/fread/fclose. Mapping in the entire file just so you
> can read 64kb is overkill.
>
> Specifically, if you fseek to the beginning of where you want to read,
> then fread what you want, the only part that will get cached is what
> you read. It will be faster than not caching.
>
> mapping the file then reading from memory also caches parts of the
> file, but only what you read.
>
> If you're going to read your file in large chunks then it will be
> faster to use the open(), lseek(), read() and close() system calls.
> The "f" calls from stdio use an in-process cache which is faster for
> small accesses but slower for large ones.
>
>
> --
> Don Quixote de la Mancha
> Dulcinea Technologies Corporation
> Software of Elegance and Beauty
> http://www.dulcineatech.com
> email@hidden
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