src/Instance.h

   1 /*
   2  * Copyright (C) 1996-2021 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_INSTANCE_H
  10 #define SQUID_INSTANCE_H
  11
  12 #if HAVE_SYS_TYPES_H
  13 #include <sys/types.h>
  14 #endif
  15
  16 /// code related to Squid Instance and PID file management
  17 namespace Instance {
  18
  19 /// Usually throws if another Squid instance is running. False positives are
  20 /// highly unlikely, but the caller must tolerate false negatives well:
  21 /// We may not detect another running instance and, hence, may not throw.
  22 /// Does nothing if PID file maintenance is disabled.
  23 void ThrowIfAlreadyRunning();
  24
  25 /// Creates or updates the PID file for the current process.
  26 /// Does nothing if PID file maintenance is disabled.
  27 void WriteOurPid();
  28
  29 /// \returns another Squid instance PID
  30 /// Throws if PID file maintenance is disabled.
  31 pid_t Other();
  32
  33 } // namespace Instance
  34
  35 #endif
  36