2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2005, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure
6 * This program 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 2 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, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * See the "LEGAL", "LICENSE", "CREDITS" and "README" files for all the
23 * related information and legal notices. It is expected that any future
24 * projects/authors will amend these files as needed.
28 * empthread.h: Definitions for Empire threading
30 * Known contributors to this file:
37 * This header defines Empire's abstract thread interface. There are
38 * several concrete implementations.
40 * Empire threads are non-preemptive, i.e. they run until they
41 * voluntarily yield the processor. The thread scheduler then picks
42 * one of the runnable threads with the highest priority. Priorities
43 * are static. Empire code relies on these properties heavily. The
44 * most common form of yielding the processor is sleeping for some
54 /* Abstract data types */
56 /* empth_t * represents a thread. */
57 typedef struct lwpProc empth_t;
59 /* empth_sem_t * represents a semaphore */
60 typedef struct lwpSem empth_sem_t;
62 /* Flags for empth_select(): whether to sleep on input or output */
63 #define EMPTH_FD_READ LWP_FD_READ
64 #define EMPTH_FD_WRITE LWP_FD_WRITE
66 /* Flags for empth_init() and empth_create() */
67 /* Request debug prints */
68 #define EMPTH_PRINT LWP_PRINT
69 /* Request stack checking */
70 #define EMPTH_STACKCHECK LWP_STACKCHECK
72 #endif /* EMPTH_LWP */
76 #define EMPTH_FD_READ 0x1
77 #define EMPTH_FD_WRITE 0x2
79 #define EMPTH_PRINT 0x1
80 #define EMPTH_STACKCHECK 0x2
82 typedef struct empth_t empth_t;
83 typedef struct empth_sem_t empth_sem_t;
85 #endif /* EMPTH_POSIX */
88 /* The Windows NT Threads */
89 #define EMPTH_FD_READ 0x1
90 #define EMPTH_FD_WRITE 0x2
92 #define EMPTH_PRINT 0x1
93 #define EMPTH_STACKCHECK 0x2
95 typedef struct loc_Thread_t empth_t;
96 typedef struct loc_Sem_t empth_sem_t;
98 void empth_request_shutdown(void);
99 #endif /* EMPTH_W32 */
102 * Initialize thread package.
103 * CTX points to a thread context variable; see empth_create().
104 * FLAGS request optional features.
105 * Should return 0 on success, -1 on error, but currently always
108 int empth_init(void **ctx, int flags);
111 * Create a new thread.
112 * PRIO is the scheduling priority.
113 * ENTRY is the entry point. It will be called with argument UD.
114 * Thread stack is at least SIZE bytes.
115 * FLAGS should be the same as were passed to empth_init(), or zero.
116 * NAME is the threads name, and DESC its description. These are used
117 * 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 * Return the thread, or NULL on error.
123 empth_t *empth_create(int prio, void (*entry)(void *),
124 int size, int flags, char *name, char *desc, void *ud);
127 * Return the current thread.
129 empth_t *empth_self(void);
132 * Terminate the current thread.
135 void empth_exit(void);
138 * Yield the processor.
140 void empth_yield(void);
144 * THREAD will not be scheduled again. Instead, it will terminate as
145 * if it executed empth_exit(). It is unspecified when exactly that
147 * THREAD must not be the current thread.
149 void empth_terminate(empth_t *thread);
152 * Put current thread to sleep until file descriptor FD is ready for I/O.
153 * If FLAGS & EMPTH_FD_READ, wake up if FD is ready for input.
154 * If FLAGS & EMPTH_FD_WRITE, wake up if FD is ready for output.
155 * At most one thread may sleep on the same file descriptor.
156 * Note: Currently, Empire sleeps only on network I/O, i.e. FD is a
157 * socket. Implementations should not rely on that.
159 void empth_select(int fd, int flags);
162 * Awaken THREAD if it is sleeping in empth_select().
163 * Note: This must not awaken threads sleeping in other functions.
165 void empth_wakeup(empth_t *thread);
168 * Put current thread to sleep until the time is UNTIL.
169 * May sleep somehwat longer, but never shorter.
171 void empth_sleep(time_t until);
174 * Create a semaphore.
175 * NAME is its name, it is used for debugging.
176 * COUNT is the initial count value of the semaphore, it must not be
178 * Return the semaphore, or NULL on error.
180 empth_sem_t *empth_sem_create(char *name, int count);
184 * Increase SEM's count. If threads are sleeping on it, wake up
185 * exactly one of them. If that thread has a higher priority, yield
187 * This semaphore operation is often called `down' or `V' otherwhere.
189 void empth_sem_signal(empth_sem_t *sem);
193 * If SEM has a zero count, put current thread to sleep until
194 * empth_sem_signal() awakens it. SEM will have non-zero value then.
195 * Decrement SEM's count.
196 * This semaphore operation is often called `up' or `P' otherwhere.
198 void empth_sem_wait(empth_sem_t *sem);