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gh-115304: Add doc for initialize PyMutex as global variables #115305

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Merged
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Feb 21, 2024
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gh-115304: Add doc for initialize PyMutex as global variables #115305

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gh-115304: Correct the typical initialization of PyMutex in its comme…
aisk Feb 11, 2024
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aisk Feb 17, 2024
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Update Include/internal/pycore_lock.h
aisk Feb 21, 2024
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2 changes: 1 addition & 1 deletion Include/internal/pycore_lock.h
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Expand Up @@ -26,7 +26,7 @@ extern "C" {
// 0b11: locked and has parked threads
//
// Typical initialization:
// PyMutex m = (PyMutex){0};
// PyMutex m = {0};
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I don't think we should make this change. The comment is for variables that need explicit initialization, such as local variables and fields in heap allocated structures. Static variables are implicitly initialized to zero in C.

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Maybe instead we can add an additional example of statically initializing the PyMutex?

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Thanks for the review! For local variables, should we remove the cast (PyMutex)? Seems it is needless in modern C.

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Most commonly, we are initializing fields in a struct like:

self->mutex = (PyMutex){0};

You can't write:

self->mutex = {0};  // INVALID!

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Ah, I've got the point!

//
// Typical usage:
// PyMutex_Lock(&m);
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