Questions tagged [file-mapping]
87 questions
0
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3 answers
match 2 strings exactly except at places where there is a particular string in python
I have a master file which contains certain text- let's say-
file contains x
the image is of x type
the user is admin
the address is x
and then there 200 other text files containing texts like-
file contains xyz
the image if of abc type
the user is…
user2715898
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How prevent multiple instances of a same module inside my app?
I have code below and my problem is related to foo() function.
The problem is that when foo() is executed in a infinite loop with a interval between each execution, is loaded a copy of same dll ( FileName ) that already is present in my app.
Eg:…
user7661932
0
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0 answers
Memory mapping some data between 2 processes - C++
So I have a first process (process1.cpp) which takes the list of the current processes in the system and should write them in the shared memory alongside their PID and PPID:
addr = (LPTSTR)MapViewOfFile(hMapFile,
FILE_MAP_ALL_ACCESS,
0,
…
miTzuliK
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1 answer
Why doesn't this file-mapped variable get flushed to the disk?
I recently realized that my C skills got a bit rusty and decided to play a bit. I just ended up with a weird behavior though - the file-mapped memory I requested doesn't seem to flush the variable ifs.free_space. The result is that if you don't…
d33tah
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2 answers
How to use shared memory correctly under windows
I'm kind of new to shared memory and i was searching for a working example, i managed to find only over MSDN
On the first process i've declared my shared memory as following:
hFileMapping = ::CreateFileMapping(INVALID_HANDLE_VALUE, nullptr,…
igal k
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0 answers
How to fragmentary map large text file in memory using Visual C++?
I have a large plain text file with size of 20GB on disk. Lets name this file as "MyFile.txt". This file contains only english languge words and one string with value of "+++". Lets name this string as FlagString. From the beginig of MyFile.txt to…
user3769902
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0 answers
How to CopyMemory to copy struct using FileMapping?
I have following code, after CopyMemory my pBuf is empty, it contains no data from newCommand, or when I want to add something in that struct it doesnt work... What am I doing wrong?
struct StCommand
{
TCHAR sourcePath[MAX_PATH];
TCHAR…
Jakub
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0
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1 answer
How Message reads value by taking LPTSTR variable as parameters in visual c++?
I tried an example from MSDN that shows how to read and write using fileMapping functions. I am pasting the code here for you reference from MSDN. The link is…
Ravee S Gohiel
- 79
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0
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1 answer
error when access data from boost mapped_region
I have some trouble when visit mapped_region data.
First, I define a struct: (for stock quotes...)
struct bar{
double open,high,low,close;
size_t volume;
bar(double _open, double _high, double _low, double _close): open(_open),high(_high),…
user3217264
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- 1
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0 answers
problems with .Net File Mapping
There are two processes:
Win32, C++ - writer
.Net 4.5, C# - reader
first process creates a buffer and sharing for second process.
(int)(buffer+0) - until when you can write.
(int)(buffer+4) - until when you can read.
... - block…
0
votes
1 answer
Returning boost::interprocess memory-mapped file from function?
How can I put this code in to a function so that I pass a file path and it returns the file-mapped bytes in to a char array? Whenever I have tried I can never read the contents once the function finishes?
using boost::interprocess;
using…
user997112
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0
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1 answer
WaitForSingleObject on a semaphore does not wait, returns immediately
I'm trying to make a simple client-server program using windows file mapping and that uses semaphores. The clients send to the server 2 numbers, the server computes nr1+nr2 and nr1 * nr2. I tried something but it doesn't even work for 1 client and I…
MathMe
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0 answers
C++ MapVirtualFileEx - Creating multiple maps for faster access
I am using MapVirtualFile to quickly access data from a file.
However, this is too slow.
I guess it is because the file is huge (300 mb), and I need to read from different locations (for example from the start of the file, then from the end of the…
tmighty
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1 answer
FileMapped write access
I try to write to file while it is opened as file mapped from another process and it fails.
Please look at fragments of code:
access = GENERIC_READ | GENERIC_WRITE;
share = FILE_SHARE_READ | FILE_SHARE_WRITE;
disposition = OPEN_EXISTING;
HANDLE…
Edward83
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0
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1 answer
File mapping opening (Windows)
How correctly open/use file mapping on Windows with ability to write to it from another process without file mapping;
For example process A writes big log file, it open file, write new data to the end, or rewrite it with new data.
Process B in…
Edward83
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