Re^3: How to access the contents of a specific memory address?

What do you want know on perl's memory allocation?

If you want a 1 second glimpse, run

use Devel::Peek;
$num = 5;
Dump($num);
print $num."\n";
Dump($num);
[download]

Output

SV = IV(0xbf4958) at 0xbf495c
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 5
5
SV = PVIV(0x39df74) at 0xbf495c
  REFCNT = 1
  FLAGS = (IOK,POK,pIOK,pPOK)
  IV = 5
  PV = 0x84cb0c "5"\0
  CUR = 1
  LEN = 4
[download]

If you want to know more, read illguts. Someone on perlmonks is bound to know whatever you ask about Perl's C side.

Comment on Re^3: How to access the contents of a specific memory address? Select or Download Code

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Re^4: How to access the contents of a specific memory address? by pat_mc (Pilgrim) on Jul 30, 2012 at 19:54 UTC
Yes, this is taking me half the way I wanted to go. I can use Devel::Peek to inspect variables and their location in memory. What I really wanted to do, however, was to go the other way: to find out which value is currently stored in a specific memory location. Is there a way Devel::Peek will provide this information, too?	[reply]
Re^5: How to access the contents of a specific memory address? by bulk88 (Priest) on Jul 30, 2012 at 20:14 UTC
Yes, this is taking me half the way I wanted to go. I can use Devel::Peek to inspect variables and their location in memory. What I really wanted to do, however, was to go the other way: to find out which value is currently stored in a specific memory location. Is there a way Devel::Peek will provide this information, too? I am confused. Are you saying "I have a PV /char from an unknown SV, I want to find out what SV * does this PV /char belong to, how can I do this?"? This might be possible to do BTW. Or are you asking, I have a PV /char , I want to find out how long is the allocation according to the malloc system? If I understand "to find out which value is currently stored in a specific memory location." in isolation, you want to read a memory block into the Perl language. That involves unpack(), and was shown to you before in this thread.	[reply]