What is the difference between “stdcall” and “invoke” in FASM? Give examples.

In FASM, `stdcall` and `invoke` are both used to call a function. However, they differ in their syntax and the way they handle function arguments.

`stdcall` is a calling convention that specifies the order and manner in which function arguments are passed and the order in which registers are saved and restored. It is commonly used with Windows API functions. The syntax for using `stdcall` in FASM is:

stdcall function_name, arg1, arg2, ..., argn

Here, `function_name` is the name of the function being called, and `arg1` through `argn` are the arguments being passed to the function.

For example, to call the `MessageBoxA` function from the Windows API using `stdcall`, you would write:

stdcall MessageBoxA, 0, message, caption, MB_OK

`invoke`, on the other hand, is a macro that simplifies the syntax for calling functions. It automatically generates the code for setting up the stack, pushing the arguments, and calling the function. The syntax for using `invoke` in FASM is:

invoke function_name, arg1, arg2, ..., argn

For example, to call the `MessageBoxA` function from the Windows API using `invoke`, you would write:

invoke MessageBoxA, 0, message, caption, MB_OK

Note that `invoke` automatically adds the `stdcall` calling convention for Windows API functions, so you don't need to explicitly specify it.

In summary, `stdcall` is a calling convention that specifies the order and manner in which function arguments are passed, while `invoke` is a macro that simplifies the syntax for calling functions by automatically generating code for setting up the stack, pushing the arguments, and calling the function.