[fpc-pascal] FPC and Memory

Alexey Pavluchenko pavluchenko at isp.kiev.ua
Thu Apr 28 13:52:29 CEST 2005

Hello Pianoman,

Thursday, April 28, 2005, 1:44:43 PM, you wrote:

P> Yes, this is interisting but I'd like for example to create a memory image
P> of some part of ram to see exactly what is there. In old dos days it was
P> possible to do like for i:=0 to 65535 do for j:=0 to 15 do
P> write(f,mem[i,j]); or similarly. But how can be done this in Windows?

Here's an excerpt from WinAPI reference:

=== cut ===
The ReadProcessMemory function reads memory in a specified process.
The entire area to be read must be accessible, or the operation fails.

BOOL ReadProcessMemory(

    HANDLE  hProcess,   // handle of the process whose memory is read  
    LPCVOID  lpBaseAddress,     // address to start reading
    LPVOID  lpBuffer,   // address of buffer to place read data
    DWORD  cbRead,      // number of bytes to read
    LPDWORD  lpNumberOfBytesRead        // address of number of bytes read


Identifies an open handle of a process whose memory is read. The
handle must have PROCESS_VM_READ access to the process.


Points to the base address in the specified process to be read. Before
any data transfer occurs, the system verifies that all data in the
base address and memory of the specified size is accessible for read
access. If this is the case, the function proceeds; otherwise, the
function fails.


Points to a buffer that receives the contents from the address space
of the specified process.


Specifies the requested number of bytes to read from the specified


Points to the actual number of bytes transferred into the specified
buffer. If lpNumberOfBytesRead is NULL, the parameter is ignored.

Return Value

If the function succeeds, the return value is TRUE.
If the function fails, the return value is FALSE. To get extended
error information, call GetLastError.
The function fails if the requested read operation crosses into an
area of the process that is inaccessible.


ReadProcessMemory copies the data in the specified address range from
the address space of the specified process into the specified buffer
of the current process. Any process that has a handle with
PROCESS_VM_READ access can call the function. The process whose
address space is read is typically, but not necessarily, being
The entire area to be read must be accessible. If it is not, the
function fails as noted previously.

See Also

=== cut ===

Best regards,

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