Partly answering myself: For some reason, right after mystdout has been created, i now have to do mystdout.seek(0) and this solves the issue.
No idea why though.. Le jeu. 11 avr. 2024 à 14:42, Olivier B. <perso.olivier.barthel...@gmail.com> a écrit : > > I am trying to use StringIO to capture stdout, in code that looks like this: > > import sys > from io import StringIO > old_stdout = sys.stdout > sys.stdout = mystdout = StringIO() > print( "patate") > mystdout.seek(0) > sys.stdout = old_stdout > print(mystdout.read()) > > Well, it is not exactly like this, since this works properly > > This code is actually run from C++ using the C Python API. > This worked quite well, so the code was right at some point. But now, > two things changed: > - Now using python 3.11.7 instead of 3.7.12 > - Now using only the python limited C API > > And it seems that now, mystdout.read() always misses the first two > characters that have been written to stdout. > > My first ideas was something related to the BOM improperly truncated > at some point, but i am manipulating UTF-8, so the bom would be 3 > bytes, not 2. > > I ruled out wrong C++ code to extract the string from the python > variable, since running a python print of the content of mystdout in > the real stdout also misses the two first characters. > > Hopefully someone has a clue on what would have changed in Python for > this to stop working compared to python 3.7? -- https://mail.python.org/mailman/listinfo/python-list
