2 * Copyright (C) 1984-2021 Mark Nudelman
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
7 * For more information, see the README file.
12 * Operating system dependent routines.
14 * Most of the stuff in here is based on Unix, but an attempt
15 * has been made to make things work on other operating systems.
16 * This will sometimes result in a loss of functionality, unless
17 * someone rewrites code specifically for the new operating system.
19 * The makefile provides defines to decide whether various
20 * Unix features are present.
26 #if MSDOS_COMPILER==WIN32C
39 #if HAVE_POLL && !MSDOS_COMPILER && !defined(__APPLE__)
49 * BSD setjmp() saves (and longjmp() restores) the signal mask.
50 * This costs a system call or two per setjmp(), so if possible we clear the
51 * signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead.
52 * On other systems, setjmp() doesn't affect the signal mask and so
53 * _setjmp() does not exist; we just use setjmp().
55 #if HAVE__SETJMP && HAVE_SIGSETMASK
56 #define SET_JUMP _setjmp
57 #define LONG_JUMP _longjmp
59 #define SET_JUMP setjmp
60 #define LONG_JUMP longjmp
65 static jmp_buf read_label;
68 extern int ignore_eoi;
75 * Return true if one of the events has occurred on the specified file.
78 poll_events(fd, events)
82 struct pollfd poller = { fd, events, 0 };
83 int n = poll(&poller, 1, 0);
86 return (poller.revents & events);
91 * Like read() system call, but is deliberately interruptible.
92 * A call to intread() from a signal handler will interrupt
93 * any pending iread().
104 #if MSDOS_COMPILER==WIN32C
108 #if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
120 if (SET_JUMP(read_label))
123 * We jumped here from intread.
130 sigprocmask(SIG_SETMASK, &mask, NULL);
146 #if MSDOS_COMPILER==DJGPPC
150 * Don't try reading from a TTY until a character is
151 * available, because that makes some background programs
152 * believe DOS is busy in a way that prevents those
153 * programs from working while "less" waits.
158 FD_SET(fd, &readfds);
159 if (select(fd+1, &readfds, 0, 0, 0) == -1)
164 if (ignore_eoi && fd != tty)
166 if (poll_events(tty, POLLIN) && getchr() == CONTROL('X'))
171 if (poll_events(fd, POLLERR|POLLHUP))
178 #if MSDOS_COMPILER==WIN32C
179 if (win32_kbhit() && WIN32getch() == CONTROL('X'))
186 n = read(fd, buf, len);
189 * This is a kludge to workaround a problem on some systems
190 * where terminating a remote tty connection causes read() to
191 * start returning 0 forever, instead of -1.
196 static int consecutive_nulls = 0;
200 consecutive_nulls = 0;
201 if (consecutive_nulls > 20)
211 * Certain values of errno indicate we should just retry the read.
213 #if MUST_DEFINE_ERRNO
231 * Interrupt a pending iread().
236 LONG_JUMP(read_label, 1);
240 * Return the current time.
256 * Local version of strerror, if not available from the system.
264 extern char *sys_errlist[];
268 return sys_errlist[err];
270 sprintf(buf, "Error %d", err);
276 * errno_message: Return an error message based on the value of "errno".
279 errno_message(filename)
286 #if MUST_DEFINE_ERRNO
293 len = (int) (strlen(filename) + strlen(p) + 3);
294 m = (char *) ecalloc(len, sizeof(char));
295 SNPRINTF2(m, len, "%s: %s", filename, p);
299 /* #define HAVE_FLOAT 0 */
302 muldiv(val, num, den)
303 POSITION val, num, den;
306 double v = (((double) val) * num) / den;
307 return ((POSITION) (v + 0.5));
309 POSITION v = ((POSITION) val) * num;
313 return (POSITION) (v / den);
315 /* Above calculation overflows;
316 * use a method that is less precise but won't overflow. */
317 return (POSITION) (val / (den / num));
322 * Return the ratio of two POSITIONS, as a percentage.
323 * {{ Assumes a POSITION is a long int. }}
330 return (int) muldiv(num, (POSITION) 100, den);
334 * Return the specified percentage of a POSITION.
337 percent_pos(pos, percent, fraction)
342 /* Change percent (parts per 100) to perden (parts per NUM_FRAC_DENOM). */
343 POSITION perden = (percent * (NUM_FRAC_DENOM / 100)) + (fraction / 100);
347 return (POSITION) muldiv(pos, perden, (POSITION) NUM_FRAC_DENOM);
352 * strchr is used by regexp.c.
359 for ( ; *s != '\0'; s++)
370 memcpy(dst, src, len)
375 char *dstp = (char *) dst;
376 char *srcp = (char *) src;
379 for (i = 0; i < len; i++)
388 * This implements an ANSI-style intercept setup for Microware C 3.2
391 os9_signal(type, handler)
393 RETSIGTYPE (*handler)();
406 if (_gs_opt(f, &sgbuf) < 0)
408 return (sgbuf.sg_class == 0);
417 #if MSDOS_COMPILER==WIN32C
422 struct timespec t = { sec, (ms - sec*1000) * 1000000 };
428 sleep((ms+999) / 1000);