Support for read-only memory?

[GerbenAbbink]

Is it possible to allocate memory with FastMM5 and make part of that memory read-only?

[pleriche]

Hi Gerben,

Unfortunately PC hardware only supports memory protection at the page level, which is 4096 bytes. You could allocate a block via FastMM and then call VirtualProtect to change the page the block is in to read-only mode, but you'll run into trouble if the adjacent blocks are written to by your application.

Alternatively you could allocate a 4K page via VirtualAlloc yourself, and then you can control the protection flags on that page without risk to adjacent blocks.

Best regards,
Pierre

[GerbenAbbink]

Yes, that is what I wanted. Thank you.

…

On Sat, Jul 30, 2022 at 11:00 AM Pierre le Riche ***@***.***> wrote: Hi Gerben, Unfortunately PC hardware only supports memory protection at the page level, which is 4096 bytes. You could allocate a block via FastMM and then call VirtualProtect to change the page the block is in to read-only mode, but you'll run into trouble if the adjacent blocks are written to by your application. Alternatively you could allocate a 4K page via VirtualAlloc yourself, and then you can control the protection flags on that page without risk to adjacent blocks. Best regards, Pierre — Reply to this email directly, view it on GitHub <#29 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACCGIDYXFUS7YI2N3OVEJH3VWTVIRANCNFSM55C3GWLA> . You are receiving this because you authored the thread.Message ID: ***@***.***>