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
51 /* thread priorities */
66 /* Abstract data types */
68 /* empth_t * represents a thread. */
69 typedef struct lwpProc empth_t;
71 /* empth_sem_t * represents a semaphore */
72 typedef struct lwpSem empth_sem_t;
74 /* Flags for empth_select(): whether to sleep on input or output */
75 #define EMPTH_FD_READ LWP_FD_READ
76 #define EMPTH_FD_WRITE LWP_FD_WRITE
78 /* Flags for empth_init() and empth_create() */
79 /* Request debug prints */
80 #define EMPTH_PRINT LWP_PRINT
81 /* Request stack checking */
82 #define EMPTH_STACKCHECK LWP_STACKCHECK
84 #endif /* EMPTH_LWP */
88 #define EMPTH_FD_READ 0x1
89 #define EMPTH_FD_WRITE 0x2
91 #define EMPTH_PRINT 0x1
92 #define EMPTH_STACKCHECK 0x2
94 typedef struct empth_t empth_t;
95 typedef struct empth_sem_t empth_sem_t;
97 #endif /* EMPTH_POSIX */
100 /* The Windows NT Threads */
101 #define EMPTH_FD_READ 0x1
102 #define EMPTH_FD_WRITE 0x2
104 #define EMPTH_PRINT 0x1
105 #define EMPTH_STACKCHECK 0x2
107 typedef struct loc_Thread_t empth_t;
108 typedef struct loc_Sem_t empth_sem_t;
110 void empth_request_shutdown(void);
111 #endif /* EMPTH_W32 */
114 * Initialize thread package.
115 * CTX points to a thread context variable; see empth_create().
116 * FLAGS request optional features.
117 * Should return 0 on success, -1 on error, but currently always
120 int empth_init(void **ctx, int flags);
123 * Create a new thread.
124 * PRIO is the scheduling priority.
125 * ENTRY is the entry point. It will be called with argument UD.
126 * Thread stack is at least SIZE bytes.
127 * FLAGS should be the same as were passed to empth_init(), or zero.
128 * NAME is the threads name, and DESC its description. These are used
129 * for logging and debugging.
130 * UD is the value to pass to ENTRY. It is also assigned to the
131 * context variable defined with empth_init() whenever the thread gets
133 * Return the thread, or NULL on error.
135 empth_t *empth_create(int prio, void (*entry)(void *),
136 int size, int flags, char *name, char *desc, void *ud);
139 * Return the current thread.
141 empth_t *empth_self(void);
144 * Terminate the current thread.
147 void empth_exit(void);
150 * Yield the processor.
152 void empth_yield(void);
156 * THREAD will not be scheduled again. Instead, it will terminate as
157 * if it executed empth_exit(). It is unspecified when exactly that
159 * THREAD must not be the current thread.
161 void empth_terminate(empth_t *thread);
164 * Put current thread to sleep until file descriptor FD is ready for I/O.
165 * If FLAGS & EMPTH_FD_READ, wake up if FD is ready for input.
166 * If FLAGS & EMPTH_FD_WRITE, wake up if FD is ready for output.
167 * At most one thread may sleep on the same file descriptor.
168 * Note: Currently, Empire sleeps only on network I/O, i.e. FD is a
169 * socket. Implementations should not rely on that.
171 void empth_select(int fd, int flags);
174 * Awaken THREAD if it is sleeping in empth_select().
175 * Note: This must not awaken threads sleeping in other functions.
177 void empth_wakeup(empth_t *thread);
180 * Put current thread to sleep until the time is UNTIL.
181 * May sleep somehwat longer, but never shorter.
183 void empth_sleep(time_t until);
186 * Create a semaphore.
187 * NAME is its name, it is used for debugging.
188 * COUNT is the initial count value of the semaphore, it must not be
190 * Return the semaphore, or NULL on error.
192 empth_sem_t *empth_sem_create(char *name, int count);
196 * Increase SEM's count. If threads are sleeping on it, wake up
197 * exactly one of them. If that thread has a higher priority, yield
199 * This semaphore operation is often called `down' or `V' otherwhere.
201 void empth_sem_signal(empth_sem_t *sem);
205 * If SEM has a zero count, put current thread to sleep until
206 * empth_sem_signal() awakens it. SEM will have non-zero value then.
207 * Decrement SEM's count.
208 * This semaphore operation is often called `up' or `P' otherwhere.
210 void empth_sem_wait(empth_sem_t *sem);