2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2016, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure, Markus Armbruster
6 * Empire is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * See files README, COPYING and CREDITS in the root of the source
22 * tree for related information and legal notices. It is expected
23 * that future projects/authors will amend these files as needed.
27 * empthread.h: Definitions for Empire threading
29 * Known contributors to this file:
33 * Markus Armbruster, 2005-2012
34 * Ron Koenderink, 2005-2009
38 * This header defines Empire's abstract thread interface. There are
39 * several concrete implementations.
41 * Empire threads are non-preemptive, i.e. they run until they
42 * voluntarily yield the processor. The thread scheduler then picks
43 * one of the runnable threads. The most common form of yielding the
44 * processor is sleeping for some event to happen.
56 /* Abstract data types */
59 typedef struct lwpProc empth_t;
61 /* A read-write lock, perferring writers */
62 typedef struct lwp_rwlock empth_rwlock_t;
64 /* Flags for empth_select(): whether to sleep on input or output */
65 #define EMPTH_FD_READ LWP_FD_READ
66 #define EMPTH_FD_WRITE LWP_FD_WRITE
68 /* Flags for empth_init() and empth_create() */
69 /* Request debug prints */
70 #define EMPTH_PRINT LWP_PRINT
71 /* Request stack checking */
72 #define EMPTH_STACKCHECK LWP_STACKCHECK
74 #endif /* EMPTH_LWP */
77 #define EMPTH_FD_READ 0x1
78 #define EMPTH_FD_WRITE 0x2
80 #define EMPTH_PRINT 0x1
81 #define EMPTH_STACKCHECK 0x2
83 typedef struct empth_t empth_t;
84 typedef struct empth_rwlock_t empth_rwlock_t;
86 #endif /* EMPTH_POSIX */
89 /* The Windows NT Threads */
90 #define EMPTH_FD_READ 0x1
91 #define EMPTH_FD_WRITE 0x2
93 #define EMPTH_PRINT 0x1
94 #define EMPTH_STACKCHECK 0x2
96 typedef struct loc_Thread empth_t;
97 typedef struct loc_RWLock empth_rwlock_t;
99 void empth_request_shutdown(void);
100 #endif /* EMPTH_W32 */
103 * Initialize thread package.
104 * @ctx points to a thread context variable; see empth_create().
105 * @flags request optional features.
106 * Should return 0 on success, -1 on error, but currently always
109 int empth_init(void **ctx, int flags);
112 * Create a new thread.
113 * @entry is the entry point. It will be called with argument @ud.
114 * If it returns, the thread terminates as if it called empth_exit().
115 * Thread stack is at least @size bytes.
116 * @flags should be the same as were passed to empth_init(), or zero.
117 * @name is the thread's name, it is used for logging and debugging.
118 * @ud is the value to pass to @entry. It is also assigned to the
119 * context variable defined with empth_init() whenever the thread gets
121 * Yield the processor.
122 * Return the thread, or NULL on error.
124 empth_t *empth_create(void (*entry)(void *),
125 int size, int flags, char *name, void *ud);
128 * Return the current thread, NULL before empth_init().
129 * This is the only function that may be called before empth_init().
131 empth_t *empth_self(void);
134 * Return @thread's name.
136 char *empth_name(empth_t *thread);
139 * Set @thread's name to @name.
141 void empth_set_name(empth_t *thread, char *name);
144 * Terminate the current thread.
145 * The current thread should not be the thread that executed main().
146 * If it is, implementations may terminate the process rather than the
150 void empth_exit(void);
153 * Yield the processor.
155 void empth_yield(void);
158 * Put current thread to sleep until file descriptor @fd is ready for I/O.
159 * If @flags & EMPTH_FD_READ, wake up if @fd is ready for input.
160 * If @flags & EMPTH_FD_WRITE, wake up if @fd is ready for output.
161 * At most one thread may sleep on the same file descriptor.
162 * @timeout, if non-null, limits the sleep time.
163 * Return one when the @fd is ready, zero on timeout or early wakeup by
164 * empth_wakeup(), -1 on error with errno set.
165 * Note: Currently, Empire sleeps only on network I/O, i.e. @fd is a
166 * socket. Implementations should not rely on that.
168 int empth_select(int fd, int flags, struct timeval *timeout);
171 * Awaken @thread if it is sleeping in empth_select() or empth_sleep().
172 * This does not awaken threads sleeping in other functions.
173 * Does not yield the processor.
175 void empth_wakeup(empth_t *thread);
178 * Put current thread to sleep until the time is @until.
179 * Return 0 if it slept until that time.
180 * Return -1 if woken up early, by empth_wakeup().
182 int empth_sleep(time_t until);
185 * Put current thread to sleep until SIGHUP, SIGINT or SIGTERM is received.
186 * Return the signal number.
188 int empth_wait_for_signal(void);
191 * Create a read-write lock.
192 * @name is its name, it is used for debugging.
193 * Return the read-write lock, or NULL on error.
195 empth_rwlock_t *empth_rwlock_create(char *name);
200 void empth_rwlock_destroy(empth_rwlock_t *rwlock);
203 * Lock @rwlock for writing.
204 * A read-write lock can be locked for writing only when it is
205 * unlocked. If this is not the case, put the current thread to sleep
208 void empth_rwlock_wrlock(empth_rwlock_t *rwlock);
211 * Lock @rwlock for reading.
212 * A read-write lock can be locked for reading only when it is not
213 * locked for writing, and no other thread is attempting to lock it
214 * for writing. If this is not the case, put the current thread to
217 void empth_rwlock_rdlock(empth_rwlock_t *rwlock);
220 * Unlock read-write lock @rwlock.
221 * The current thread must hold @rwlock.
222 * Wake up threads that can now lock it.
224 void empth_rwlock_unlock(empth_rwlock_t *rwlock);
228 * Stuff for implementations, not for clients.
231 void empth_init_signals(void);