libmdbx/src/options.h

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/* Support for huge write-transactions */
#ifndef MDBX_HUGE_TRANSACTIONS
#define MDBX_HUGE_TRANSACTIONS 0
#endif /* MDBX_HUGE_TRANSACTIONS */

/* using fcntl(F_FULLFSYNC) with 5-10 times slowdown */
#define MDBX_OSX_WANNA_DURABILITY 0
/* using fsync() with chance of data lost on power failure */
#define MDBX_OSX_WANNA_SPEED 1

#ifndef MDBX_OSX_SPEED_INSTEADOF_DURABILITY
#define MDBX_OSX_SPEED_INSTEADOF_DURABILITY MDBX_OSX_WANNA_DURABILITY
#endif /* MDBX_OSX_SPEED_INSTEADOF_DURABILITY */

/* Controls checking PID against reuse DB environment after the fork() */
#ifndef MDBX_TXN_CHECKPID
#if defined(MADV_DONTFORK) || defined(_WIN32) || defined(_WIN64)
/* PID check could be ommited:
 *  - on Linux when madvise(MADV_DONTFORK) is available. i.e. after the fork()
 *    mapped pages will not be available for child process.
 *  - in Windows where fork() not available. */
#define MDBX_TXN_CHECKPID 0
#else
#define MDBX_TXN_CHECKPID 1
#endif
#define MDBX_TXN_CHECKPID_CONFIG "AUTO=" STRINGIFY(MDBX_TXN_CHECKPID)
#else
#define MDBX_TXN_CHECKPID_CONFIG STRINGIFY(MDBX_TXN_CHECKPID)
#endif /* MDBX_TXN_CHECKPID */

/* Controls checking transaction owner thread against misuse transactions from
 * other threads. */
#ifndef MDBX_TXN_CHECKOWNER
#define MDBX_TXN_CHECKOWNER 1
#define MDBX_TXN_CHECKOWNER_CONFIG "AUTO=" STRINGIFY(MDBX_TXN_CHECKOWNER)
#else
#define MDBX_TXN_CHECKOWNER_CONFIG STRINGIFY(MDBX_TXN_CHECKOWNER)
#endif /* MDBX_TXN_CHECKOWNER */

/* Does a system have battery-backed Real-Time Clock or just a fake. */
#ifndef MDBX_TRUST_RTC
#if defined(__linux__) || defined(__gnu_linux__) || defined(__NetBSD__) ||     \
    defined(__OpenBSD__)
#define MDBX_TRUST_RTC 0 /* a lot of embedded systems have a fake RTC */
#else
#define MDBX_TRUST_RTC 1
#endif
#define MDBX_TRUST_RTC_CONFIG "AUTO=" STRINGIFY(MDBX_TRUST_RTC)
#else
#define MDBX_TRUST_RTC_CONFIG STRINGIFY(MDBX_TRUST_RTC)
#endif /* MDBX_TRUST_RTC */

//------------------------------------------------------------------------------

#define MDBX_LOCKING_WIN32FILES -1  /* Win32 File Locking API */
#define MDBX_LOCKING_SYSV 5         /* SystemV IPC semaphores */
#define MDBX_LOCKING_POSIX1988 1988 /* POSIX-1 Shared anonymous semaphores */
#define MDBX_LOCKING_POSIX2001 2001 /* POSIX-2001 Shared Mutexes */
#define MDBX_LOCKING_POSIX2008 2008 /* POSIX-2008 Robust Mutexes */
#define MDBX_LOCKING_BENAPHORE 1995 /* BeOS Benaphores, aka Futexes */

#if defined(_WIN32) || defined(_WIN64)
#define MDBX_LOCKING MDBX_LOCKING_WIN32FILES
#else
#ifndef MDBX_LOCKING
#if defined(_POSIX_THREAD_PROCESS_SHARED) &&                                   \
    _POSIX_THREAD_PROCESS_SHARED >= 200112L && !defined(__FreeBSD__)

/* Some platforms define the EOWNERDEAD error code even though they
 * don't support Robust Mutexes. If doubt compile with -MDBX_LOCKING=2001. */
#if defined(EOWNERDEAD) && _POSIX_THREAD_PROCESS_SHARED >= 200809L &&          \
    ((defined(_POSIX_THREAD_ROBUST_PRIO_INHERIT) &&                            \
      _POSIX_THREAD_ROBUST_PRIO_INHERIT > 0) ||                                \
     (defined(_POSIX_THREAD_ROBUST_PRIO_PROTECT) &&                            \
      _POSIX_THREAD_ROBUST_PRIO_PROTECT > 0) ||                                \
     defined(PTHREAD_MUTEX_ROBUST) || defined(PTHREAD_MUTEX_ROBUST_NP)) &&     \
    (!defined(__GLIBC__) ||                                                    \
     __GLIBC_PREREQ(2, 10) /* troubles with Robust mutexes before 2.10 */)
#define MDBX_LOCKING MDBX_LOCKING_POSIX2008
#else
#define MDBX_LOCKING MDBX_LOCKING_POSIX2001
#endif
#elif defined(__sun) || defined(__SVR4) || defined(__svr4__)
#define MDBX_LOCKING MDBX_LOCKING_POSIX1988
#else
#define MDBX_LOCKING MDBX_LOCKING_SYSV
#endif
#define MDBX_LOCKING_CONFIG "AUTO=" STRINGIFY(MDBX_LOCKING)
#else
#define MDBX_LOCKING_CONFIG STRINGIFY(MDBX_LOCKING)
#endif /* MDBX_LOCKING */
#endif /* !Windows */

#ifndef MDBX_USE_OFDLOCKS
#if defined(F_OFD_SETLK) && defined(F_OFD_SETLKW) && defined(F_OFD_GETLK) &&   \
    !defined(MDBX_SAFE4QEMU) &&                                                \
    !defined(__sun) /* OFD-lock are broken on Solaris */
#define MDBX_USE_OFDLOCKS 1
#else
#define MDBX_USE_OFDLOCKS 0
#endif
#define MDBX_USE_OFDLOCKS_CONFIG "AUTO=" STRINGIFY(MDBX_USE_OFDLOCKS)
#else
#define MDBX_USE_OFDLOCKS_CONFIG STRINGIFY(MDBX_USE_OFDLOCKS)
#endif /* MDBX_USE_OFDLOCKS */

//------------------------------------------------------------------------------

#ifndef MDBX_CPU_WRITEBACK_INCOHERENT
#if defined(__ia32__) || defined(__e2k__) || defined(__hppa) ||                \
    defined(__hppa__)
#define MDBX_CPU_WRITEBACK_INCOHERENT 0
#else
#define MDBX_CPU_WRITEBACK_INCOHERENT 1
#endif
#endif /* MDBX_CPU_WRITEBACK_INCOHERENT */

#ifndef MDBX_MMAP_INCOHERENT_FILE_WRITE
#ifdef __OpenBSD__
#define MDBX_MMAP_INCOHERENT_FILE_WRITE 1
#else
#define MDBX_MMAP_INCOHERENT_FILE_WRITE 0
#endif
#endif /* MDBX_MMAP_INCOHERENT_FILE_WRITE */

#ifndef MDBX_MMAP_INCOHERENT_CPU_CACHE
#if defined(__mips) || defined(__mips__) || defined(__mips64) ||               \
    defined(__mips64__) || defined(_M_MRX000) || defined(_MIPS_) ||            \
    defined(__MWERKS__) || defined(__sgi)
/* MIPS has cache coherency issues. */
#define MDBX_MMAP_INCOHERENT_CPU_CACHE 1
#else
/* LY: assume no relevant mmap/dcache issues. */
#define MDBX_MMAP_INCOHERENT_CPU_CACHE 0
#endif
#endif /* MDBX_MMAP_INCOHERENT_CPU_CACHE */

#ifndef MDBX_64BIT_ATOMIC
#if MDBX_WORDBITS >= 64
#define MDBX_64BIT_ATOMIC 1
#else
#define MDBX_64BIT_ATOMIC 0
#endif
#define MDBX_64BIT_ATOMIC_CONFIG "AUTO=" STRINGIFY(MDBX_64BIT_ATOMIC)
#else
#define MDBX_64BIT_ATOMIC_CONFIG STRINGIFY(MDBX_64BIT_ATOMIC)
#endif /* MDBX_64BIT_ATOMIC */

#ifndef MDBX_64BIT_CAS
#if defined(ATOMIC_LLONG_LOCK_FREE)
#if ATOMIC_LLONG_LOCK_FREE > 1
#define MDBX_64BIT_CAS 1
#else
#define MDBX_64BIT_CAS 0
#endif
#elif defined(__GCC_ATOMIC_LLONG_LOCK_FREE)
#if __GCC_ATOMIC_LLONG_LOCK_FREE > 1
#define MDBX_64BIT_CAS 1
#else
#define MDBX_64BIT_CAS 0
#endif
#elif defined(__CLANG_ATOMIC_LLONG_LOCK_FREE)
#if __CLANG_ATOMIC_LLONG_LOCK_FREE > 1
#define MDBX_64BIT_CAS 1
#else
#define MDBX_64BIT_CAS 0
#endif
#elif defined(_MSC_VER) || defined(__APPLE__)
#define MDBX_64BIT_CAS 1
#else
#define MDBX_64BIT_CAS MDBX_64BIT_ATOMIC
#endif
#define MDBX_64BIT_CAS_CONFIG "AUTO=" STRINGIFY(MDBX_64BIT_CAS)
#else
#define MDBX_64BIT_CAS_CONFIG STRINGIFY(MDBX_64BIT_CAS)
#endif /* MDBX_64BIT_CAS */

#if !defined(MDBX_UNALIGNED_OK)
#if defined(_MSC_VER)
#define MDBX_UNALIGNED_OK 1 /* avoid MSVC misoptimization */
#elif __CLANG_PREREQ(5, 0) || __GNUC_PREREQ(5, 0)
#define MDBX_UNALIGNED_OK 0 /* expecting optimization is well done */
#elif (defined(__ia32__) || defined(__ARM_FEATURE_UNALIGNED)) &&               \
    !defined(__ALIGNED__)
#define MDBX_UNALIGNED_OK 1
#else
#define MDBX_UNALIGNED_OK 0
#endif
#endif /* MDBX_UNALIGNED_OK */

#ifndef MDBX_CACHELINE_SIZE
#if defined(SYSTEM_CACHE_ALIGNMENT_SIZE)
#define MDBX_CACHELINE_SIZE SYSTEM_CACHE_ALIGNMENT_SIZE
#elif defined(__ia64__) || defined(__ia64) || defined(_M_IA64)
#define MDBX_CACHELINE_SIZE 128
#else
#define MDBX_CACHELINE_SIZE 64
#endif
#endif /* MDBX_CACHELINE_SIZE */

/*******************************************************************************
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