Re: How to access the contents of a specific memory address?

Basically the posts here not with standing:
The answer is NO.

Perl cannot access an absolute physical memory address.

In "C" there are ways to "map" a piece of physical memory to an array - maybe for memory mapped I/O?
But such a thing has to run as a kernel process (device driver, etc).

A user process like Perl simply cannot do it. Thats it.

A user process can access its own DATA space, but this is an offset from a physical address of which the user process is completely unaware - the hardware does some magic. Since Perl is a "user" process, it cannot know and it cannot access an actual physical memory address like say, "0x000" - the OS will prevent such a thing - its just that simple. NO, Absolutely NOT!

Comment on Re: How to access the contents of a specific memory address?

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Re^2: How to access the contents of a specific memory address? by BrowserUk (Patriarch) on Jul 30, 2012 at 01:16 UTC
In "C" there are ways to "map" a piece of physical memory ... Since Perl ... cannot access an actual physical memory address. Sorry, but I think you are just muddying the waters with this post. The OP didn't ask how to do that. Nowhere in the OP did he mention "physical memory", just a specific memory address & the memory address of a given variable & a given memory address; all of which are generically taken to mean: addresses within the virtual address space of the current process unless explicitly qualified otherwise. Outside the auspices of deep technical discussion at the operating system or hardware level, this -- along with your other occasional overreach in to technicalities: there's no such thing as a file -- just come across as clever dickiness rather than constructive attempts to help. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. The start of some sanity?	[reply]
Re^3: How to access the contents of a specific memory address? by Marshall (Canon) on Jul 30, 2012 at 08:00 UTC
Ok. My effort failed. My intent was not to be "dicky" whatever that means. So what is the best practical "how to" answer for the OP?	[reply]
Re^4: How to access the contents of a specific memory address? by BrowserUk (Patriarch) on Jul 30, 2012 at 13:29 UTC
So what is the best practical "how to" answer for the OP? bulk88 has already given that answer in How to access the contents of a specific memory address?. The long and short of which is that: it is possible to obtain access to raw address values of the PV component of Perl scalars using pack 'p' & 'P'; but there is not much that you can usefully do with them once obtained. Any attempt to manipulate pointers obtained that way -- beyond reading the contents of the memory the point at -- will simply segfault. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. The start of some sanity?	[reply]


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