# Open binary file stream to read a portion of file

**URL:** <https://forums.unrealengine.com/t/open-binary-file-stream-to-read-a-portion-of-file/373885>\
**Category:** C++\
**Tags:** unreal-engine, UE4, CPP, question\
**Created:** [October 20, 2016, 8:32am UTC](https://forums.unrealengine.com/t/open-binary-file-stream-to-read-a-portion-of-file/373885 "2016-10-20T08:32:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![anonymous\_user\_2f46fb931](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_2f46fb931](https://forums.unrealengine.com/u/anonymous_user_2f46fb931)\
**Post date:** [October 20, 2016, 8:32am UTC](https://forums.unrealengine.com/t/open-binary-file-stream-to-read-a-portion-of-file/373885/1 "2016-10-20T08:32:06Z")

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Hi,

I followed Rama’s tutorial to save and load binary files in here

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In the tutorial we load the entire file into binary array in memory, but in my case the binary files are really big, hence it is not a good idea to read the entire file at once. I would like to ask that is there anyway that I can open a file stream to read a portion of the file at a time?

Thank you very much for your help.  
Kind regards.

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**Author:** ![MaKiPL](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/makipl/32/570787_2.png) [@MaKiPL](https://forums.unrealengine.com/u/MaKiPL)\
**Post date:** [September 13, 2022, 1:10am UTC](https://forums.unrealengine.com/t/open-binary-file-stream-to-read-a-portion-of-file/373885/2 "2022-09-13T01:10:59Z")

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bump, anyone?  
FFileHelper loads whole file, but indeed, I need to create a support to read external non-UE files and I don’t want to store 800MB file in memory. If so, probably the only way so far that I see is creating a file streaming by yourself, which would need to be properly optimised/done across platforms, so probably on an interface. Maybe is there a ready marketplace plugin for that? Depends on the destination platform. Windows/Mac/Linux will all use the same std library for that, same goes for specific console (can’t hint name, NDA). The most problematic would be the mobiles which store files differently.

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**Author:** ![Emaer](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/emaer/32/570877_2.png) [@Emaer](https://forums.unrealengine.com/u/Emaer)\
**Post date:** [September 13, 2022, 8:07am UTC](https://forums.unrealengine.com/t/open-binary-file-stream-to-read-a-portion-of-file/373885/3 "2022-09-13T08:07:54Z")

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Unreal has [FPlatformFileManager](https://docs.unrealengine.com/4.27/en-US/API/Runtime/Core/HAL/FPlatformFileManager/), which gives you access to [IPlatformFile](https://docs.unrealengine.com/4.27/en-US/API/Runtime/Core/GenericPlatform/IPlatformFile/), and this interface gives you [IFileHandle](https://docs.unrealengine.com/4.27/en-US/API/Runtime/Core/GenericPlatform/IFileHandle/)