[Bug]: Cygwin build fails due to use of Windows-only functions in _tkagg.cpp #22997
Description
Bug summary
When the build gets to https://github.com/matplotlib/matplotlib/blob/main/src/_tkagg.cpp#L262-L273 on Cygwin, the build fails with a few goto crosses initialization warnings, which are easy to fix (closed by #23051), and two error: ‘PyErr_SetFromWindowsErr’ was not declared in this scope, which are less easy to fix.
Code for reproduction
pip install matplotlibActual outcome
...
lots of compiler command lines and some warnings (`array subscript has type 'char'`)
...
gcc ... -I/usr/include/python3.8 -c src/_tkagg.cpp -o build/temp.cygwin-3.3.4-x86_64-3.8/matplotlib.backends._tkagg/src/_tkagg.o -fvisibility=hidden -flto
src/_tkagg.cpp: In function ‘void load_tkinter_funcs()’:
src/_tkagg.cpp:263:9: error: ‘PyErr_SetFromWindowsErr’ was not declared in this scope
263 | PyErr_SetFromWindowsErr(0);
| ^~~~~~~~~~~~~~~~~~~~~~~
src/_tkagg.cpp:271:9: error: ‘PyErr_SetFromWindowsErr’ was not declared in this scope
271 | PyErr_SetFromWindowsErr(0);
| ^~~~~~~~~~~~~~~~~~~~~~~
src/_tkagg.cpp:283:1: error: jump to label ‘exit’
283 | exit:
| ^~~~
src/_tkagg.cpp:272:14: note: from here
272 | goto exit;
| ^~~~
src/_tkagg.cpp:274:26: note: crosses initialization of ‘bool tk_ok’
274 | bool tcl_ok = false, tk_ok = false;
| ^~~~~
src/_tkagg.cpp:274:10: note: crosses initialization of ‘bool tcl_ok’
274 | bool tcl_ok = false, tk_ok = false;
| ^~~~~~
src/_tkagg.cpp:283:1: error: jump to label ‘exit’
283 | exit:
| ^~~~
src/_tkagg.cpp:268:14: note: from here
268 | goto exit;
| ^~~~
src/_tkagg.cpp:274:26: note: crosses initialization of ‘bool tk_ok’
274 | bool tcl_ok = false, tk_ok = false;
| ^~~~~
src/_tkagg.cpp:274:10: note: crosses initialization of ‘bool tcl_ok’
274 | bool tcl_ok = false, tk_ok = false;
| ^~~~~~
src/_tkagg.cpp:283:1: error: jump to label ‘exit’
283 | exit:
| ^~~~
src/_tkagg.cpp:264:14: note: from here
264 | goto exit;
| ^~~~
src/_tkagg.cpp:274:26: note: crosses initialization of ‘bool tk_ok’
274 | bool tcl_ok = false, tk_ok = false;
| ^~~~~
src/_tkagg.cpp:274:10: note: crosses initialization of ‘bool tcl_ok’
274 | bool tcl_ok = false, tk_ok = false;
| ^~~~~~
error: command '/usr/bin/gcc' failed with exit code 1
...
pip reminds me this is not pip's fault
Expected outcome
...
Successfully installed collected packages: matplotlib
Additional information
Cygwin 3.3.4
GCC 11.2.0
Python 3.8.12
I've installed matplotlib in earlier versions. #17415 rather suggests that Cygwin builds worked at that time, and probably made using the default backend somewhat easier. #22445 seems to be where the PyErr_SetFromWindowsErr calls came in.
I've attempted to create a dummy PyErr_SetFromWindowsErr on Cygwin, but, given the number of failures in the test suite, I probably didn't do it right.
Operating system
Cygwin 3.3.4 on Windows 10
Matplotlib Version
3.5.2
Matplotlib Backend
TkAgg
Python version
3.8.12
Jupyter version
N/A
Installation
pip