Hello, I haven't found any answer on this - if it is possible or not.
I have a PCI card with a memory on it. I have also a driver (written in
C++) that maps the memory from the card to user mode - I need very fast
access to this memory, that's why I need to map it directly to my
program.
And now comes my problem - I want to write the control program in c#.
Is there any way how to access to the mapped memory? It is in user
space, I know its size in runtime (not in compile-time), I get its
address using IOCTL from the driver. Now I need to "map" it on Int32
array or something like that...
Martin 4 2357
Martin wrote: Is there any way how to access to the mapped memory? It is in user space, I know its size in runtime (not in compile-time), I get its address using IOCTL from the driver. Now I need to "map" it on Int32 array or something like that...
Have a look at the IntPtr and Marshal classes. IntPtr represents an
address in memory. And Marshal provides methods for reading/writing to
that memory (using the Copy, ReadXXX and WriteXXX methods).
hth,
Max
"Martin" <zi***@centrum. cz> wrote in message
news:11******** *************@v 46g2000cwv.goog legroups.com...
| Hello, I haven't found any answer on this - if it is possible or not.
|
| I have a PCI card with a memory on it. I have also a driver (written in
|
| C++) that maps the memory from the card to user mode - I need very fast
|
| access to this memory, that's why I need to map it directly to my
| program.
|
|
| And now comes my problem - I want to write the control program in c#.
|
|
| Is there any way how to access to the mapped memory? It is in user
| space, I know its size in runtime (not in compile-time), I get its
| address using IOCTL from the driver. Now I need to "map" it on Int32
| array or something like that...
|
|
| Martin
|
If you can afford the marshaling overhead, you can use the Marshal class to
pass data from the unmanaged to the managed heap, if not, you will have to
resort to unsafe constructs using native pointers.
Willy.
Really is there no other way than unsafe and pointers?
In fact in the hardware there are just input and output buffers and
some fifos - and I need fast access to both of the types of memories. I
need only two special types of access to the memory - large data copy
(memcpy in C) and fast access to one address for read/write.
I'm afraid that Marshal class means lots of copying thus it will slow
down the access, am I right?
Martin
"Martin" <zi***@centrum. cz> wrote in message
news:11******** **************@ j33g2000cwa.goo glegroups.com.. .
| Really is there no other way than unsafe and pointers?
|
| In fact in the hardware there are just input and output buffers and
| some fifos - and I need fast access to both of the types of memories. I
| need only two special types of access to the memory - large data copy
| (memcpy in C) and fast access to one address for read/write.
|
| I'm afraid that Marshal class means lots of copying thus it will slow
| down the access, am I right?
|
| Martin
|
It depends, if you need the unmanaged data to be available as a managed type
(an array of ..), you'll have to copy it somehow.
To do this in C# you have two options, or you can use unsafe code pointers,
or you move the data using Marshal.Copy.
The latter option is your best bet, it's safer, and on V2, it's actually
faster than using unsafe & pointers.
However, if you don't need the unmanaged data to be available as a managed
type, your best option in C# is to access the data directly using unsafe &
pointers.
Willy. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: Darryl |
last post by:
I am receiving this error when try to insert a value into the Summary
field that is formatted in HTML. I am using ASP to connect to an Access
database. The ASP code for the insert statement is as follows:
Private Function fInsertRecord()
sSql = "INSERT INTO Events (Description, TheTime, Location, Event,
Download, DateOfEvent, Summary)...
|
by: Douglas Bell |
last post by:
i get this error sometimes when accessing the database throug my web brouser
Driver={Microsoft Access Driver
(*.mdb)};DBQ=C:\Inetpub\wwwroot\fpdb\asplogin.mdb;
what can i do to fix it
it still works i cant see any problems
most of the times when i refresh it goes away
|
by: stueyh |
last post by:
When attempting to connect to an Access 2000 DB using ADO.Net from within
ASP.Net running under an impersonated local user account receiving the
following error.
ERROR Disk or network
error. ERROR Driver's
SQLSetConnectAttr failed ERROR Disk or network error
Oracle ODBC connection works fine under the same user so assuming this is...
|
by: Reza Nabi |
last post by:
Dear All:
I have been developing ASP.NET application on MS Access database using ODBC.
When I was trying to save more than 255 chars in a Memo field I got the
following error.
ERROR Invalid precision
value
Below is the code snippet of two function where it is breaking. Any advice
on this would be greatly appreciated.
|
by: somersbar |
last post by:
hello all,
im trying to connect to a microsoft access database from an ASP.NET web
form.
i keep getting the following error though:
ERROR Could not use
'(unknown)'; file already in use. ERROR Driver's SQLSetConnectAttr failed ERROR
Could not use '(unknown)';
file already in use.
| |
by: bazzer |
last post by:
hey,
i am using visual basic.net 2003 and have an ASP.NET webform
application thats accessing a microsoft access 2003 database. i kept
getting the following error when i tried to run it:
ERROR General error
Unable to open registry key 'Temporary (volatile) Jet DSN for process
0x8fc Thread 0x934 DBC 0x437b94 Jet'. ERROR Driver's...
|
by: bazzer |
last post by:
hey,
im trying to access a microsoft access database from an ASP.NET web
application in visual basic 2003.NET. i get the following error when i
try running it:
Server Error in '/CinemaBookingSystem' Application.
--------------------------------------------------------------------------------
ERROR General error
Unable to open registry...
|
by: Martin |
last post by:
Hello, I haven't found any answer on this - if it is possible or not.
I have a PCI card with a memory on it. I have also a driver (written in
C++) that maps the memory from the card to user mode - I need very fast
access to this memory, that's why I need to map it directly to my
program.
And now comes my problem - I want to write the...
|
by: Beorne |
last post by:
I have imported a corporate image handling COM object in my C#
project.
To access in a fast way the memory of the image there is a method that
returns a pointer to the memory (in byte) of the underlying image.
This method can be used to read as well to rewrite the pixel values.
In the interface .idl file the method is declared as:
...
|
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...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language...
| |
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the...
|
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...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes...
|
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...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
|
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...
| |