Questions about mmap()

[Unknown Soldier]

Hello,

I have a couple queries about mmap() that ppl here might be able to help
with.

1. What's the best way to resize an mmap()d area when you've enlarged
the file? Can you call mmap() again with the existing mapped location,
or do you need to remap it from scratch?

2. If I have a file descriptor returned by a call to socket(), can I
used mmap() as an alterantive to read()? Will there be problems
depending on whether the socket is blocking?

Thanks.

[Dann Corbit]

"Unknown Soldier" <no****@nospam. comwrote in message
news:ft******** **@aioe.org...

Hello,

I have a couple queries about mmap() that ppl here might be able to help
with.

1. What's the best way to resize an mmap()d area when you've enlarged the
file? Can you call mmap() again with the existing mapped location, or do
you need to remap it from scratch?

You want news:comp.unix. programmer
Here is the POSIX reference:
http://www.opengroup.org/onlinepubs/.../xsh/mmap.html

2. If I have a file descriptor returned by a call to socket(), can I used
mmap() as an alterantive to read()? Will there be problems depending on
whether the socket is blocking?

I am curious about what you expect to gain by memory mapping a socket.
** Posted from http://www.teranews.com **

[Dann Corbit]

"Dann Corbit" <dc*****@connx. comwrote in message
news:7d******** **********@news .teranews.com.. .

"Unknown Soldier" <no****@nospam. comwrote in message
news:ft******** **@aioe.org...

>Hello,

I have a couple queries about mmap() that ppl here might be able to help
with.

1. What's the best way to resize an mmap()d area when you've enlarged the
file? Can you call mmap() again with the existing mapped location, or do
you need to remap it from scratch?

You want news:comp.unix. programmer
Here is the POSIX reference:
http://www.opengroup.org/onlinepubs/.../xsh/mmap.html

>2. If I have a file descriptor returned by a call to socket(), can I used
mmap() as an alterantive to read()? Will there be problems depending on
whether the socket is blocking?

I am curious about what you expect to gain by memory mapping a socket.

<Supremely OT>
I guess that there is a benefit:
Multiple outstanding I/O operations on a single file descriptor using
threads:
http://www.squid-cache.org/mail-arch...9805/0139.html
</Supremely OT>
** Posted from http://www.teranews.com **

[Keith Thompson]

Unknown Soldier <no****@nospam. comwrites:

I have a couple queries about mmap() that ppl here might be able to
help with.

[snip]

Some people here might try, but you'll get better answers in
comp.unix.progr ammer. The mmap() function is defined by POSIX, not by
the C language standard.

--
Keith Thompson (The_Other_Keit h) <ks***@mib.or g>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[Antoninus Twink]

On 8 Apr 2008 at 20:18, Dann Corbit wrote:

"Dann Corbit" <dc*****@connx. comwrote in message

>I am curious about what you expect to gain by memory mapping a socket.

I guess that there is a benefit:
Multiple outstanding I/O operations on a single file descriptor using
threads:
http://www.squid-cache.org/mail-arch...9805/0139.html

That's an interesting (albeit bizarre) idea... as far as I can see,
though, all the sample code on that page first mmaps a file, then
read()s from a socket into the mmap'd area, rather than actually
attempting to mmap the socket itself.

[Flash Gordon]

Unknown Soldier wrote, On 08/04/08 20:50:

Hello,

I have a couple queries about mmap() that ppl here might be able to help
with.

<snip>

The people over on comp.unix.progr ammer are more likely to be able to
provide quality help on this since I am guessing you are using the Unix
mmap function. mmap is a system extension rather than being part of the
C language as defined by the C standard.
--
Flash Gordon

[Jack Klein]

On Tue, 08 Apr 2008 20:50:23 +0100, Unknown Soldier
<no****@nospam. comwrote in comp.lang.c:

Hello,

I have a couple queries about mmap() that ppl here might be able to help
with.

ppl doesn't participate in this group any more. We killed him and ate
his liver.

--
Jack Klein
Home: http://JK-Technology.Com
FAQs for
comp.lang.c http://c-faq.com/
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alt.comp.lang.l earn.c-c++
http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html

[ppl]

Jack Klein wrote:

ppl doesn't participate in this group any more. We killed him and ate
his liver.

But... Why?

[Gordon Burditt]

>ppl doesn't participate in this group any more. We killed him and ate

>his liver.

But... Why?

Friends don't let friends void main().