Cheat Engine

[supercharger]

is it possible to call a function in another process & and in the memory space of that process ?
and is it possible to cause a process to stop at a certain EIP ?
i am thinking of using an EXE or Python to control another process with minimal modification of codes in the target process.
although i can inject codes into a process, i wish i had a quicker way of development, in spite of the low running performance.

[Chris12]

Yes its possible and relatively easy.
It basically works exactly like a normal code injection.
You can even use the code injection template with CE.

For more automatic control write a lua script that creates a code injection at the EIP you want and check some global variable to decide if you want to jump to exit process or not.

You can get the "ExitProcess()" function with GetProcAddress.

[supercharger]

sorry i didn't express precisely. i should say 'pause' instead of 'stop', i didn't mean to exit a process.

the scenario that i imagined is like this, for example:

a game has functions that draw images or text on screen,
but drawing must be called at a certain EIP (a little sooner or later), or the graphics will be cleared (initialized).
if i want to use the built-in functions to draw some extra images or text, i should inject some codes at the EIP, normally i use DLL here.

but writing/compiling/loading/unloading DLL take quite some time,

so i wish i could use another process(ideally with Python) to pause the game process at an EIP, then call the functions in the game process, then unpause the game process.
because Python has an interactive mode - pause a program and allow me to alter the program then unpause the program. this can be quicker than handling DLL. what's more, writing in Python is much faster than writing ASM. this helps development.

i don't know about many features in CE, i don't know LUA script either. and CE should not be a companion of games, it's only for the time of development, when development is done, CE should not be required. a game should run by itself or with only one specialized trainer running at the background.

so can it be done without CE?
or should i use some features in CE for the time of development then compile DLL when i am sure about the codes?
but sometimes i have to write hundreds lines of code in ASM before i can conclude that the planned feature can work correctly.
does CE help in that situation?

[atom0s]

If you want to pause a process you can use SuspendThread on the processes main thread. (Wow64SuspendThread for 64bit processes.)

[Dark Byte]

Or use NtSuspendProcess(processhandle) from ntdll.dll