src/dyldLock.h

   1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
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  24
  25
  26 #ifndef __DYLDLOCK__
  27 #define __DYLDLOCK__
  28
  29 //
  30 // This file contains the synchronization utilities used to make dyld APIs be thread safe.
  31 //
  32 // The implementation of all dyld API's must hold acquire global lock (in libSystem)
  33 // before calling into dyld proper, and release the lock after returning from dyld.
  34 // This is done using the macros DYLD_LOCK_THIS_BLOCK.
  35 // Example:
  36 //
  37 //  void dyld_api() {
  38 //              DYLD_LOCK_THIS_BLOCK;
  39 //              // free to do stuff here
  40 //              // that accesses dyld internal data structures
  41 //      }
  42 //
  43 //  void dyld_api_state_free() {
  44 //              DYLD_NO_LOCK_THIS_BLOCK
  45 //              // can only do stuff here
  46 //              // that does not require locking
  47 //      }
  48 //
  49
  50 #define DYLD_LOCK_THIS_BLOCK                    LockHelper _dyld_lock;
  51 #define DYLD_NO_LOCK_THIS_BLOCK
  52
  53 // used by dyld wrapper functions in libSystem
  54 class __attribute__((visibility("hidden"))) LockHelper
  55 {
  56 public:
  57         LockHelper();
  58         ~LockHelper();
  59 };
  60
  61
  62 // to initialize
  63 extern void dyldGlobalLockInitialize()          __attribute__((visibility("hidden")));
  64 extern void dyldGlobalLockAcquire()                     __attribute__((visibility("hidden")));
  65 extern void dyldGlobalLockRelease()                     __attribute__((visibility("hidden")));
  66
  67 #endif // __DYLDLOCK__
  68