Author Wrzlprmft
Recipients Wrzlprmft
Date 2020-04-17.08:54:26
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According to the C-API documentation¹ for `Py_BuildValue`:

> The characters space, tab, colon and comma are ignored in format strings (but not within format units such as s#). This can be used to make long format strings a tad more readable.

However format strings such as `"(d )"` cause the error:

> Unmatched paren in format

By contrast `"( d)"` and `"(d d)"` cause no problems. I therefore assume that tuples are not considered “format units” in the sense of the above quote and this is a bug. Alternatively, the documentation needs clarification.

I could reproduce this problem with Python 3.7 and 3.8. I did not try other versions.

Appended is a minimal C extension exhibiting the problem. I compile and run with:

gcc -fPIC -I/usr/include/python3.8 -c foo.c -o foo.o
gcc -shared foo.o -o
python3.8 -c "import foo;"


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