cpython/Include/pythread.h

#ifndef Py_PYTHREAD_H
#define Py_PYTHREAD_H

typedef void *PyThread_type_lock;

#ifdef __cplusplus
extern "C" {
#endif

/* Return status codes for Python lock acquisition.  Chosen for maximum
 * backwards compatibility, ie failure -> 0, success -> 1.  */
typedef enum PyLockStatus {
    PY_LOCK_FAILURE = 0,
    PY_LOCK_ACQUIRED = 1,
    PY_LOCK_INTR
} PyLockStatus;

PyAPI_FUNC(void) PyThread_init_thread(void);
PyAPI_FUNC(unsigned long) PyThread_start_new_thread(void (*)(void *), void *);
PyAPI_FUNC(void) _Py_NO_RETURN PyThread_exit_thread(void);
PyAPI_FUNC(unsigned long) PyThread_get_thread_ident(void);

#if defined(__APPLE__) || defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(_WIN32) || defined(_AIX)
#define PY_HAVE_THREAD_NATIVE_ID
PyAPI_FUNC(unsigned long) PyThread_get_thread_native_id(void);
#endif

PyAPI_FUNC(PyThread_type_lock) PyThread_allocate_lock(void);
PyAPI_FUNC(void) PyThread_free_lock(PyThread_type_lock);
PyAPI_FUNC(int) PyThread_acquire_lock(PyThread_type_lock, int);
#define WAIT_LOCK       1
#define NOWAIT_LOCK     0

/* PY_TIMEOUT_T is the integral type used to specify timeouts when waiting
   on a lock (see PyThread_acquire_lock_timed() below).
   PY_TIMEOUT_MAX is the highest usable value (in microseconds) of that
   type, and depends on the system threading API.

   NOTE: this isn't the same value as `_thread.TIMEOUT_MAX`.  The _thread
   module exposes a higher-level API, with timeouts expressed in seconds
   and floating-point numbers allowed.
*/
#define PY_TIMEOUT_T long long

#if defined(_POSIX_THREADS)
   /* PyThread_acquire_lock_timed() uses _PyTime_FromNanoseconds(us * 1000),
      convert microseconds to nanoseconds. */
#  define PY_TIMEOUT_MAX (LLONG_MAX / 1000)
#elif defined (NT_THREADS)
   // WaitForSingleObject() accepts timeout in milliseconds in the range
   // [0; 0xFFFFFFFE] (DWORD type). INFINITE value (0xFFFFFFFF) means no
   // timeout. 0xFFFFFFFE milliseconds is around 49.7 days.
#  if 0xFFFFFFFELL * 1000 < LLONG_MAX
#    define PY_TIMEOUT_MAX (0xFFFFFFFELL * 1000)
#  else
#    define PY_TIMEOUT_MAX LLONG_MAX
#  endif
#else
#  define PY_TIMEOUT_MAX LLONG_MAX
#endif


/* If microseconds == 0, the call is non-blocking: it returns immediately
   even when the lock can't be acquired.
   If microseconds > 0, the call waits up to the specified duration.
   If microseconds < 0, the call waits until success (or abnormal failure)

   microseconds must be less than PY_TIMEOUT_MAX. Behaviour otherwise is
   undefined.

   If intr_flag is true and the acquire is interrupted by a signal, then the
   call will return PY_LOCK_INTR.  The caller may reattempt to acquire the
   lock.
*/
PyAPI_FUNC(PyLockStatus) PyThread_acquire_lock_timed(PyThread_type_lock,
                                                     PY_TIMEOUT_T microseconds,
                                                     int intr_flag);

PyAPI_FUNC(void) PyThread_release_lock(PyThread_type_lock);

PyAPI_FUNC(size_t) PyThread_get_stacksize(void);
PyAPI_FUNC(int) PyThread_set_stacksize(size_t);

#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
PyAPI_FUNC(PyObject*) PyThread_GetInfo(void);
#endif


/* Thread Local Storage (TLS) API
   TLS API is DEPRECATED.  Use Thread Specific Storage (TSS) API.

   The existing TLS API has used int to represent TLS keys across all
   platforms, but it is not POSIX-compliant.  Therefore, the new TSS API uses
   opaque data type to represent TSS keys to be compatible (see PEP 539).
*/
Py_DEPRECATED(3.7) PyAPI_FUNC(int) PyThread_create_key(void);
Py_DEPRECATED(3.7) PyAPI_FUNC(void) PyThread_delete_key(int key);
Py_DEPRECATED(3.7) PyAPI_FUNC(int) PyThread_set_key_value(int key,
                                                          void *value);
Py_DEPRECATED(3.7) PyAPI_FUNC(void *) PyThread_get_key_value(int key);
Py_DEPRECATED(3.7) PyAPI_FUNC(void) PyThread_delete_key_value(int key);

/* Cleanup after a fork */
Py_DEPRECATED(3.7) PyAPI_FUNC(void) PyThread_ReInitTLS(void);


#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03070000
/* New in 3.7 */
/* Thread Specific Storage (TSS) API */

typedef struct _Py_tss_t Py_tss_t;  /* opaque */

PyAPI_FUNC(Py_tss_t *) PyThread_tss_alloc(void);
PyAPI_FUNC(void) PyThread_tss_free(Py_tss_t *key);

/* The parameter key must not be NULL. */
PyAPI_FUNC(int) PyThread_tss_is_created(Py_tss_t *key);
PyAPI_FUNC(int) PyThread_tss_create(Py_tss_t *key);
PyAPI_FUNC(void) PyThread_tss_delete(Py_tss_t *key);
PyAPI_FUNC(int) PyThread_tss_set(Py_tss_t *key, void *value);
PyAPI_FUNC(void *) PyThread_tss_get(Py_tss_t *key);
#endif  /* New in 3.7 */

#ifndef Py_LIMITED_API
#  define Py_CPYTHON_PYTHREAD_H
#  include "cpython/pythread.h"
#  undef Py_CPYTHON_PYTHREAD_H
#endif

#ifdef __cplusplus
}
#endif
#endif /* !Py_PYTHREAD_H */