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#ifndef Py_INTERNAL_GIL_H

#define Py_INTERNAL_GIL_H

#ifdef __cplusplus

extern "C" {

#endif

#ifndef Py_BUILD_CORE

# error "this header requires Py_BUILD_CORE define"

#endif

#include "pycore_condvar.h" // PyCOND_T

#ifndef Py_HAVE_CONDVAR

# error You need either a POSIX-compatible or a Windows system!

#endif

/* Enable if you want to force the switching of threads at least

every `interval`. */

#undef FORCE_SWITCHING

#define FORCE_SWITCHING

struct _gil_runtime_state {

#ifdef Py_GIL_DISABLED

/* If this GIL is disabled, enabled == 0.

If this GIL is enabled transiently (most likely to initialize a module

of unknown safety), enabled indicates the number of active transient

requests.

If this GIL is enabled permanently, enabled == INT_MAX.

It must not be modified directly; use _PyEval_EnableGILTransiently(),

_PyEval_EnableGILPermanently(), and _PyEval_DisableGIL()

It is always read and written atomically, but a thread can assume its

value will be stable as long as that thread is attached or knows that no

other threads are attached (e.g., during a stop-the-world.). */

int enabled;

#endif

/* microseconds (the Python API uses seconds, though) */

unsigned long interval;

/* Last PyThreadState holding / having held the GIL. This helps us

know whether anyone else was scheduled after we dropped the GIL. */

PyThreadState* last_holder;

/* Whether the GIL is already taken (-1 if uninitialized). This is

atomic because it can be read without any lock taken in ceval.c. */

int locked;

/* Number of GIL switches since the beginning. */

unsigned long switch_number;

/* This condition variable allows one or several threads to wait

until the GIL is released. In addition, the mutex also protects

the above variables. */

PyCOND_T cond;

PyMUTEX_T mutex;

#ifdef FORCE_SWITCHING

/* This condition variable helps the GIL-releasing thread wait for

a GIL-awaiting thread to be scheduled and take the GIL. */

PyCOND_T switch_cond;

PyMUTEX_T switch_mutex;

#endif

};

#ifdef __cplusplus

}

#endif

#endif /* !Py_INTERNAL_GIL_H */