iPhone 4s only support mmap of 1 distinct file

Originator:jp
Number:rdar://17119892 Date Originated:03-Jun-2014 09:43 AM
Status:Closed Resolved:02-Oct-2015 08:23 AM
Product:iOS Product Version:iOS 7-9
Classification:Bug Reproducible:Always
 
Summary:
mmap on iPhone 4s does only support 1 files.
Multiple mappings of the same file is possible, though.

Steps to Reproduce:
1. Open the Xcode project in this GitHub repo: https://github.com/mekjaer/ios-mmap
2. Tweak the parameters in AppDelegate.m - line 19
3. Run example on iPhone 4s

Expected Results:
Expected to be able to mmap multiple files on iPhone 4s, like on iPhone 5s and iPad Air (tested)

Actual Results:
Only possible to mmap 1 distinct file on iPhone 4s

Version:
iOS 7.1

Notes:


Configuration:
iPhone 4S

Comments

Apple Developer Relations

Engineering has provided the following information regarding this issue:

Please know that this behaves correctly. This is a deliberate limitation on the size of a process's virtual address space on 32-bit devices.

By jp at Oct. 2, 2015, 4 p.m. (reply...)

Follow up

This is still an issue with subsequent versions of iOS, including 8.x and 9.x.

By jp at Oct. 2, 2015, 4 p.m. (reply...)

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