Equivalent of Python `bytes` object

ROOT
1

Hi!

What is the equivalent of a Python bytes object in C++ from the ROOT perspective? So which function should a class exported via a dictionary (linkdef file) define, so that I can pass in a bytes object from python?

Thanks!

2

Hi,
What does the byte sequence that you want to pass contain?

For instance, this works (tried in Python2):

>>> import ROOT
>>> ROOT.gInterpreter.Declare('void f(char *s) { cout << s << endl; }')
True
>>> ROOT.f(bytes("a"))
a

Cheers,
Enric

3

Hi,
thanks for the answer! I am using python3 (sorry, should have mentioned that) and your example fails unfortunately:

>>> import ROOT
>>> ROOT.gInterpreter.Declare('void f(char *s) { cout << s << endl; }')
True
>>> ROOT.f(b"asdf")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: void ::f(char* s) =>
    could not convert argument 1

(it also fails when I use std::string). The byte array I have in my real implementation is not ascii-convertable to string…

4

Indeed I have been trying to find a conversion for bytes in Python3 and so far no luck.

So you can’t just decode your bytes object to a str, pass that string, and do whatever you want to do in C++? What is it that you want to do in C++ with these bytes?

5

Thanks for your answer!
Unfortunately, it is “real” binary data - so I do not know what to expect. So its not really any textual representation and choosing a proper encoding for this is hard.
Maybe I should think about passing a TBuffer or something…
But thanks anyways!

6

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