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| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: how to figure out the size of buffer from malloc |
| Date | 2012-02-16 14:28 -0800 |
| Organization | None to speak of |
| Message-ID | <lnmx8ifm6f.fsf@nuthaus.mib.org> (permalink) |
| References | <jhjofu$jer$1@speranza.aioe.org> |
pembed2012 <once@was.enough.invalid> writes:
> I am wondering how does 'free' know how many bytes to free? For example:
>
> char* s = (char*)malloc(10);
The cast is unnecessary and can hide errors.
char *s = malloc(10);
Note that this can fail; you should always check whether malloc()
returned a null pointer.
> free(s); // how many bytes to free?
>
> How does free know how many bytes to free? I have heard that malloc
> also allocate additional memory to hold some header information. Where
> is this header information stored? If we have access to the header, we
> can find that out?
The comp.lang.c FAQ is at <http://c-faq.com/>. You've just asked
question 7.26.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Will write code for food.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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how to figure out the size of buffer from malloc pembed2012 <once@was.enough.invalid> - 2012-02-16 20:21 +0000
Re: how to figure out the size of buffer from malloc James Kuyper <jameskuyper@verizon.net> - 2012-02-16 15:38 -0500
Re: how to figure out the size of buffer from malloc John Gordon <gordon@panix.com> - 2012-02-16 20:48 +0000
Re: how to figure out the size of buffer from malloc pembed2012 <once@was.enough.invalid> - 2012-02-16 22:42 +0000
Re: how to figure out the size of buffer from malloc John Gordon <gordon@panix.com> - 2012-02-16 22:50 +0000
Re: how to figure out the size of buffer from malloc Keith Thompson <kst-u@mib.org> - 2012-02-16 14:50 -0800
Re: how to figure out the size of buffer from malloc pembed2012 <once@was.enough.invalid> - 2012-02-17 19:45 +0000
Re: how to figure out the size of buffer from malloc China Blue Sea <chine.bleu@yahoo.com> - 2012-02-17 11:53 -0800
Re: how to figure out the size of buffer from malloc Ike Naar <ike@sverige.freeshell.org> - 2012-02-17 20:23 +0000
Re: how to figure out the size of buffer from malloc James Kuyper <jameskuyper@verizon.net> - 2012-02-17 15:33 -0500
Re: how to figure out the size of buffer from malloc pembed2012 <once@was.enough.invalid> - 2012-02-17 22:13 +0000
Re: how to figure out the size of buffer from malloc James Kuyper <jameskuyper@verizon.net> - 2012-02-17 17:25 -0500
Re: how to figure out the size of buffer from malloc Shao Miller <sha0.miller@gmail.com> - 2012-02-17 17:54 -0500
Re: how to figure out the size of buffer from malloc Keith Thompson <kst-u@mib.org> - 2012-02-17 15:01 -0800
Re: how to figure out the size of buffer from malloc Shao Miller <sha0.miller@gmail.com> - 2012-02-17 18:10 -0500
Re: how to figure out the size of buffer from malloc Ian Pilcher <arequipeno@gmail.com> - 2012-02-17 18:14 -0600
Re: how to figure out the size of buffer from malloc "BartC" <bc@freeuk.com> - 2012-02-18 11:07 +0000
Re: how to figure out the size of buffer from malloc ImpalerCore <jadill33@gmail.com> - 2012-02-18 04:40 -0800
Re: how to figure out the size of buffer from malloc Kaz Kylheku <kaz@kylheku.com> - 2012-02-18 12:48 +0000
Re: how to figure out the size of buffer from malloc Shao Miller <sha0.miller@gmail.com> - 2012-02-17 17:45 -0500
Re: how to figure out the size of buffer from malloc Shao Miller <sha0.miller@gmail.com> - 2012-02-16 22:18 -0500
Re: how to figure out the size of buffer from malloc Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-02-16 13:20 -0800
Re: how to figure out the size of buffer from malloc Lew Pitcher <lpitcher@teksavvy.com> - 2012-02-16 17:07 -0500
Re: how to figure out the size of buffer from malloc Keith Thompson <kst-u@mib.org> - 2012-02-16 14:28 -0800
Re: how to figure out the size of buffer from malloc Mark Adler <madler@alumni.caltech.edu> - 2012-02-16 23:49 -0800
Re: how to figure out the size of buffer from malloc Michael Angelo Ravera <maravera@prodigy.net> - 2012-02-18 09:54 -0800
Re: how to figure out the size of buffer from malloc gazelle@shell.xmission.com (Kenny McCormack) - 2012-02-18 18:21 +0000
Re: how to figure out the size of buffer from malloc Shao Miller <sha0.miller@gmail.com> - 2012-02-18 13:56 -0500
Re: how to figure out the size of buffer from malloc Stephen Sprunk <stephen@sprunk.org> - 2012-02-18 13:42 -0600
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