Leunsel: Added related function template.

2026-06-26T23:39:29Z

Added related function template.

Leunsel: Initial page creation.

2026-06-26T20:26:31Z

Initial page creation.

New page

[[Category:Lua]]
{{CodeBox|'''function''' mapMemory(''address'', ''size'', ''frompid'' OPTIONAL, ''topid'' OPTIONAL) ''':''' integer, integer}}

Maps a specific address range into the usermode context of another process.

The memory is mapped from the given source process ID to the given target process ID. If a process ID is 0 or not specified, the Cheat Engine process is used.

This function returns two values: the mapped address and an MDL handle. The MDL value is required when calling [[Lua:unmapMemory|unmapMemory]].

===Function Parameters===
{|width="85%" cellpadding="10%" cellspacing="0" border="0"
!align="left"|Parameter
!align="left"|Type
!style="width: 80%;background-color:white;" align="left"|Description
|-
|address
|Integer
|The address to map.
|-
|size
|Integer
|The number of bytes to map.
|-
|frompid
|Integer OPTIONAL
|The source process ID. If 0 or omitted, the Cheat Engine process is used.
|-
|topid
|Integer OPTIONAL
|The target process ID. If 0 or omitted, the Cheat Engine process is used.
|}

===Returns===
{|width="85%" cellpadding="10%" cellspacing="0" border="0"
!align="left"|Return Value
!align="left"|Type
!style="width: 80%;background-color:white;" align="left"|Description
|-
|mappedAddress
|Integer
|The mapped address in the target usermode context.
|-
|mdl
|Integer
|The MDL handle required to unmap the mapped memory with unmapMemory.
|}

===Examples===

====Map memory from the opened process to Cheat Engine====
<syntaxhighlight lang="lua" line highlight="5">
local address = getAddress("game.exe+1234")
local size = 4096
local frompid = getOpenedProcessID()

local mappedAddress, mdl = mapMemory(address, size, frompid, 0)

print(string.format("Mapped address: %X", mappedAddress))
print(string.format("MDL: %X", mdl))
</syntaxhighlight>

====Map memory and unmap it later====
<syntaxhighlight lang="lua" line highlight="5">
local address = getAddress("game.exe+1234")
local size = 4096
local frompid = getOpenedProcessID()

local mappedAddress, mdl = mapMemory(address, size, frompid, 0)

if mappedAddress ~= nil and mappedAddress ~= 0 then
print(string.format("Mapped address: %X", mappedAddress))

-- Access mapped memory here
end

if mdl ~= nil and mdl ~= 0 then
unmapMemory(mappedAddress, mdl)
end
</syntaxhighlight>

====Map memory using the default process IDs====
<syntaxhighlight lang="lua" line highlight="3">
local address = allocateMemory(4096)
local size = 4096
local mappedAddress, mdl = mapMemory(address, size)

print(string.format("Mapped address: %X", mappedAddress))

unmapMemory(mappedAddress, mdl)
</syntaxhighlight>

====Map memory from Cheat Engine to the opened process====
<syntaxhighlight lang="lua" line highlight="6">
local address = allocateMemory(4096)
local size = 4096
local frompid = 0
local topid = getOpenedProcessID()

local mappedAddress, mdl = mapMemory(address, size, frompid, topid)

print(string.format("Mapped address in target: %X", mappedAddress))

unmapMemory(mappedAddress, mdl)
</syntaxhighlight>

====Validate the returned values====
<syntaxhighlight lang="lua" line highlight="5">
local address = getAddress("game.exe+1234")
local size = 4096
local frompid = getOpenedProcessID()

local mappedAddress, mdl = mapMemory(address, size, frompid, 0)

if mappedAddress == nil or mappedAddress == 0 or mdl == nil or mdl == 0 then
print("mapMemory failed")
return
end

print("Memory mapped successfully")

unmapMemory(mappedAddress, mdl)
</syntaxhighlight>

====Read from mapped memory====
<syntaxhighlight lang="lua" line highlight="5>
local address = getAddress("game.exe+1234")
local size = 4096
local frompid = getOpenedProcessID()

local mappedAddress, mdl = mapMemory(address, size, frompid, 0)

if mappedAddress ~= nil and mappedAddress ~= 0 then
local value = readInteger(mappedAddress)

print("Value: " .. tostring(value))
end

if mdl ~= nil and mdl ~= 0 then
unmapMemory(mappedAddress, mdl)
end
</syntaxhighlight>

====Use pcall to ensure cleanup====
<syntaxhighlight lang="lua" line highlight="5">
local address = getAddress("game.exe+1234")
local size = 4096
local frompid = getOpenedProcessID()

local mappedAddress, mdl = mapMemory(address, size, frompid, 0)

local ok, err = pcall(function()
if mappedAddress ~= nil and mappedAddress ~= 0 then
print(readInteger(mappedAddress))
end
end)

if mdl ~= nil and mdl ~= 0 then
unmapMemory(mappedAddress, mdl)
end

if not ok then
print(err)
end
</syntaxhighlight>

{{LuaSeeAlso}}

← Older revision		Revision as of 23:39, 26 June 2026
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	{{LuaSeeAlso}}		{{LuaSeeAlso}}
		+
		+	{{Memory}}

Lua:mapMemory - Revision history

Leunsel: Added related function template.

Leunsel: Initial page creation.