Dear All,
I would like to implement file buffer class to make avialable
buffering mechanism to ifstream or own customized file stream.
My question is what are the semantics for seekoff, overflow, and
underflow.
When I see MS VC++6.0 STL code's basic_filebuf implementation, I
observed that it is not maintaining any buffering mechanism, instead
it is directly handling with the files. Please correct me if I am
understanding in a wrong way.
Sincerely,
Sri
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:st*****@ ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.comeaucomputing.com/csc/faq.html ] 2  1763 
"sri" <sr************ *****@yahoo.com wrote in message
news:11******** **************@ l77g2000hsb.goo glegroups.com.. .
I would like to implement file buffer class to make avialable
buffering mechanism to ifstream or own customized file stream.
My question is what are the semantics for seekoff, overflow, and
underflow.
When I see MS VC++6.0 STL code's basic_filebuf implementation, I
observed that it is not maintaining any buffering mechanism, instead
it is directly handling with the files. Please correct me if I am
understanding in a wrong way.
That's correct. The code for overflow/underflow/uflow effectively
emulates the getc/putc macros in <stdio.h>, reaching directly into
the FILE buffers. Thus, there's a single buffering mechanism that's
shared between C and C++ I/O. (No need to disable sync_with_stdio
to get good throughput.)
P.J. Plauger
Dinkumware, Ltd. http://www.dinkumware.com
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:st*****@ ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.comeaucomputing.com/csc/faq.html ]
In article <11************ **********@l77g 2000hsb.googleg roups.com>, sri
<sr************ *****@yahoo.com wrote:
uld like to implement file buffer class to make avialable
buffering mechanism to ifstream or own customized file stream.
My question is what are the semantics for seekoff, overflow, and
underflow.
Simplified for buffered streambufs
the protected virtual functions seekoff,underfl ow, overflow [and uflow]
perform the actual IO from device to buffer.
seekoff() does a relative seek similiar to fseek(),
underflow reloads buffer and returns the current char.
overflow empties the buffer and places the argument in the emptied
buffer.
---
[ comp.std.c++ is moderated. To submit articles, try just posting with ]
[ your news-reader. If that fails, use mailto:st*****@ ncar.ucar.edu ]
[ --- Please see the FAQ before posting. --- ]
[ FAQ: http://www.comeaucomputing.com/csc/faq.html ] This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
by: Stevey |
last post by:
I have the following XML file...
<?xml version="1.0"?>
<animals>
<animal>
<name>Tiger</name>
<questions>
<question index="0">true</question>
<question index="1">true</question>
</questions>
|
by: nospam |
last post by:
Ok, 3rd or is it the 4th time I have asked this question on Partial Types,
so, since it seems to me that Partial Types is still in the design or
development stages at Microsoft, I am going to ask it differently.
FOUR QUESTIONS:
The background:
I got three (3) files
|
by: |
last post by:
I can not seem to get this to compile with either gcc 3.4 or MSVC++ .NET
2003... (source follows first):
---= BEGIN MyStreamBuffer.h =---
// #IFDEF redundancy left out.
#include <streambuf>
template< class MyElem >
class MyStreamBuffer : public std::basic_streambuf< MyElem >
{
protected:
|
by: |
last post by:
I was hoping that someone (after my own failures) might post a very mininal
unbuffered derivation of basic_streambuf. My problem is that (even leaving
the buffer pointers to their defaults) uflow() never gets called unless I
define an underflow(). overflow() works as expected but I'm just trying to
start small and I can't even get that done. :(
I have also tried setting the buffer pointers using the _Init() method,
setp( 0, 0 ), setg( 0,...
|
by: |
last post by:
Is this even possible? I've found some references to specific "unbuffered"
type methods that exist in older incarnations of basic_streambuf but not in
newer ones.
Info please. :P
| | |
by: Steven T. Hatton |
last post by:
I'm a bit confused about a statement in TC++ST §13.10. It's in reference to
this example:
/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
|
by: Ekqvist Marko |
last post by:
Hi,
I have one Access database table including questions and answers. Now
I need to give answer id automatically to questionID column. But I
don't know how it is best (fastest) to do?
table before
rowID answID qryrow questionID datafield
1591 12 06e 06e 06e question
1593 12 06f 06f 06f question
1594 12 answer to the question 06f
|
by: glenn |
last post by:
I am use to programming in php and the way session and post vars are past
from fields on one page through to the post page automatically where I can
get to their values easily to write to a database or continue to process on
to the next page.
I am now trying to learn ASP to see if we can replace some of our
applications that were written in php with an ASP alternative. However,
after doing many searches on google and reading a couple...
|
by: Rider |
last post by:
Hi, simple(?) question about asp.net configuration..
I've installed ASP.NET 2.0 QuickStart Sample successfully. But, When I'm
first start application the follow message shown.
=========
Server Error in '/QuickStartv20' Application.
--------------------------------------------------------------------------------
Configuration Error
Description: An error occurred during the processing of a configuration file
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
|
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
| | |
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own....
Now, this would greatly impact the work of software developers. The idea...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| | |
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
| |
