# Porting guide for changes in IDAPython-on-Python-3 APIs

Intended audience: IDAPython developers

### Scope of this guide

IDA 7.4 [comes with the possibility of using Python 3](https://hex-rays.com/products/ida/support/ida74_idapython_python3).

Using Python 3 means that some code, which used to work, might require porting:

* `print()` becoming a function, not a statement
* `xrange` becoming `range`
* `__builtin__` becoming `builtins`
* strings being unicode and not sets of bytes
* integer division uses `//` and not `/`
* `map()` returning a map object, not a list
* `{}.iteritems()` (and similar) are gone
* some changes in the `import` mechanism
* …

Those are all well-documented Python 3 specifics, are [thoroughly documented](https://python-future.org/compatible_idioms.html), and Python even provides [tools](https://docs.python.org/2/library/2to3.html) to help with the transition.

This guide is not about those, but about IDAPython-specific changes to the API, but many of those being “ripples” of those Python 3 changes.

### The guide

Note: that all qualified names below use their originating IDAPython module’s name (e.g., `ida_kernwin`) instead of the ‘umbrella’ `idaapi` module.

| `ida_bytes.data_format_t.printf`                                  |                               | The `value` parameter used to be a `str`, now is `bytes`                                             |
| ----------------------------------------------------------------- | ----------------------------- | ---------------------------------------------------------------------------------------------------- |
| `ida_bytes.get_bytes, ida_bytes.get_bytes_and_mask`               |                               | Used to return a `str`, now returns `bytes`                                                          |
| `ida_bytes.get_strlit_contents`                                   |                               | Used to return a `str`, now returns `bytes`                                                          |
| `ida_hexrays.mbl_array_t.serialize`                               |                               | Used to return a `str`, now returns `bytes`                                                          |
| `ida_idp.IDP_Hooks.ev_assemble`                                   |                               | Used to return a `str`, now must return `bytes`                                                      |
| `ida_netnode.netnode.getblob`                                     |                               | Used to return a `str`, now returns `bytes`                                                          |
| `ida_registry.reg_read_binary`                                    |                               | Used to return a `str`, now returns `bytes`                                                          |
| `ida_typeinf.tinfo_t.serialize`                                   |                               | Used to return `str` instances for the ‘type’ and ‘fields’ parts of the tuple, now those are `bytes` |
| `ida_typeinf.get_numbered_type`                                   |                               | Used to return `str` instances for the ‘type’ and ‘fields’ parts of the tuple, now those are `bytes` |
| `ida_ua.insn_t.insnpref`                                          |                               | Used to return a `str`, now returns an `int`                                                         |
| `ida_ua.insn_t.segpref`                                           |                               | Used to return a `str`, now returns an `int`                                                         |
| `idautils._cpu.<large vector registers, such as xmm0, ymm0, ...>` |                               | Used to return a `str`, now returns `bytes`                                                          |
| `idautils.Functions.next`                                         | `idautils.Functions.__next__` | Required to turn the type into a proper iterator in Python 3                                         |