Problems reading binary data from file using QDataStream

[gowen]

Hi All,

I am very new to Qt and C++ programming in general and have got into some difficulty.

I am trying to read data from a very large binary file (upto 1GB in size) but I keep having problems.

I would like to read a certain number of bytes into a struct using QDataStream. I can compile and run the code with no errors, but it is not reading in the data that I expect.

Here is a simplified version of the code:

SomeStructure *someStruct;
 
QFile file("somedata.raw");
file.open(QIODevice::ReadOnly);
QDataStream fileStream(&file);
 
fileStream.readRawData(reinterpret_cast<char*>&someStruct, someByteSize);

SomeStructure *someStruct;

QFile file("somedata.raw");
file.open(QIODevice::ReadOnly);
QDataStream fileStream(&file);

fileStream.readRawData(reinterpret_cast<char*>&someStruct, someByteSize);

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I cannot read all the data in at once due to the size of file and would like the ability to move through the data that QDataStream gives.

I can get this to work using the ifstream, however this appears to be causing a memory issue a few lines later that I cannot correct. Therefore I thought it better to try the Qt functions for file reading.

If anyone can help then I would be so grateful! as this issue has been driving me mad!

Many Thanks