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Member "pigz-2.8/yarn.h" (13 Apr 2020, 6848 Bytes) of package /linux/privat/pigz-2.8.tar.gz:

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    1 /* yarn.h -- generic interface for thread operations
    2  * Copyright (C) 2008, 2011, 2012, 2015, 2018, 2019, 2020 Mark Adler
    3  * Version 1.7  12 Apr 2020  Mark Adler
    4  */
    6 /*
    7   This software is provided 'as-is', without any express or implied
    8   warranty.  In no event will the author be held liable for any damages
    9   arising from the use of this software.
   11   Permission is granted to anyone to use this software for any purpose,
   12   including commercial applications, and to alter it and redistribute it
   13   freely, subject to the following restrictions:
   15   1. The origin of this software must not be misrepresented; you must not
   16      claim that you wrote the original software. If you use this software
   17      in a product, an acknowledgment in the product documentation would be
   18      appreciated but is not required.
   19   2. Altered source versions must be plainly marked as such, and must not be
   20      misrepresented as being the original software.
   21   3. This notice may not be removed or altered from any source distribution.
   23   Mark Adler
   24   madler@alumni.caltech.edu
   25  */
   27 /* Basic thread operations
   29    This interface isolates the local operating system implementation of threads
   30    from the application in order to facilitate platform independent use of
   31    threads.  All of the implementation details are deliberately hidden.
   33    Assuming adequate system resources and proper use, none of these functions
   34    can fail.  As a result, any errors encountered will cause an exit() to be
   35    executed, or the execution of your own optionally-provided abort function.
   37    These functions allow the simple launching and joining of threads, and the
   38    locking of objects and synchronization of changes of objects.  The latter is
   39    implemented with a single lock type that contains an integer value.  The
   40    value can be ignored for simple exclusive access to an object, or the value
   41    can be used to signal and wait for changes to an object.
   43    -- Arguments --
   45    thread *thread;          identifier for launched thread, used by join
   46    void probe(void *);      pointer to function "probe", run when thread starts
   47    void *payload;           single argument passed to the probe function
   48    lock *lock;              a lock with a value -- used for exclusive access to
   49                             an object and to synchronize threads waiting for
   50                             changes to an object
   51    long val;                value to set lock, increment lock, or wait for
   52    int n;                   number of threads joined
   54    -- Thread functions --
   56    thread = launch(probe, payload) - launch a thread -- exit via probe() return
   57    join(thread) - join a thread and by joining end it, waiting for the thread
   58         to exit if it hasn't already -- will free the resources allocated by
   59         launch() (don't try to join the same thread more than once)
   60    n = join_all() - join all threads launched by launch() that are not joined
   61         yet and free the resources allocated by the launches, usually to clean
   62         up when the thread processing is done -- join_all() returns an int with
   63         the count of the number of threads joined (join_all() should only be
   64         called from the main thread, and should only be called after any calls
   65         of join() have completed)
   67    -- Lock functions --
   69    lock = new_lock(val) - create a new lock with initial value val (lock is
   70         created in the released state)
   71    possess(lock) - acquire exclusive possession of a lock, waiting if necessary
   72    twist(lock, [TO | BY], val) - set lock to or increment lock by val, signal
   73         all threads waiting on this lock and then release the lock -- must
   74         possess the lock before calling (twist releases, so don't do a
   75         release() after a twist() on the same lock)
   76    wait_for(lock, [TO_BE | NOT_TO_BE | TO_BE_MORE_THAN | TO_BE_LESS_THAN], val)
   77         - wait on lock value to be, not to be, be greater than, or be less than
   78         val -- must possess the lock before calling, will possess the lock on
   79         return but the lock is released while waiting to permit other threads
   80         to use twist() to change the value and signal the change (so make sure
   81         that the object is in a usable state when waiting)
   82    release(lock) - release a possessed lock (do not try to release a lock that
   83         the current thread does not possess)
   84    val = peek_lock(lock) - return the value of the lock (assumes that lock is
   85         already possessed, no possess or release is done by peek_lock())
   86    free_lock(lock) - free the resources allocated by new_lock() (application
   87         must assure that the lock is released before calling free_lock())
   89    -- Memory allocation ---
   91    yarn_mem(better_malloc, better_free) - set the memory allocation and free
   92         routines for use by the yarn routines where the supplied routines have
   93         the same interface and operation as malloc() and free(), and may be
   94         provided in order to supply thread-safe memory allocation routines or
   95         for any other reason -- by default malloc() and free() will be used
   97    -- Error control --
   99    yarn_prefix - a char pointer to a string that will be the prefix for any
  100         error messages that these routines generate before exiting -- if not
  101         changed by the application, "yarn" will be used
  102    yarn_abort - an external function that will be executed when there is an
  103         internal yarn error, due to out of memory or misuse -- this function
  104         may exit to abort the application, or if it returns, the yarn error
  105         handler will exit (set to NULL by default for no action)
  106  */
  108 extern char *yarn_prefix;
  109 extern void (*yarn_abort)(int);
  111 void yarn_mem(void *(*)(size_t), void (*)(void *));
  113 typedef struct thread_s thread;
  114 thread *launch_(void (*)(void *), void *, char const *, long);
  115 #define launch(a, b) launch_(a, b, __FILE__, __LINE__)
  116 void join_(thread *, char const *, long);
  117 #define join(a) join_(a, __FILE__, __LINE__)
  118 int join_all_(char const *, long);
  119 #define join_all() join_all_(__FILE__, __LINE__)
  121 typedef struct lock_s lock;
  122 lock *new_lock_(long, char const *, long);
  123 #define new_lock(a) new_lock_(a, __FILE__, __LINE__)
  124 void possess_(lock *, char const *, long);
  125 #define possess(a) possess_(a, __FILE__, __LINE__)
  126 void release_(lock *, char const *, long);
  127 #define release(a) release_(a, __FILE__, __LINE__)
  128 enum twist_op { TO, BY };
  129 void twist_(lock *, enum twist_op, long, char const *, long);
  130 #define twist(a, b, c) twist_(a, b, c, __FILE__, __LINE__)
  131 enum wait_op {
  132     TO_BE, /* or */ NOT_TO_BE, /* that is the question */
  134 void wait_for_(lock *, enum wait_op, long, char const *, long);
  135 #define wait_for(a, b, c) wait_for_(a, b, c, __FILE__, __LINE__)
  136 long peek_lock(lock *);
  137 void free_lock_(lock *, char const *, long);
  138 #define free_lock(a) free_lock_(a, __FILE__, __LINE__)