2 * Copyright (C) 1984-2014 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.
37 #define time_type time_t
39 #define time_type long
43 * BSD setjmp() saves (and longjmp() restores) the signal mask.
44 * This costs a system call or two per setjmp(), so if possible we clear the
45 * signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead.
46 * On other systems, setjmp() doesn't affect the signal mask and so
47 * _setjmp() does not exist; we just use setjmp().
49 #if HAVE__SETJMP && HAVE_SIGSETMASK
50 #define SET_JUMP _setjmp
51 #define LONG_JUMP _longjmp
53 #define SET_JUMP setjmp
54 #define LONG_JUMP longjmp
59 static jmp_buf read_label;
64 * Like read() system call, but is deliberately interruptible.
65 * A call to intread() from a signal handler will interrupt
66 * any pending iread().
77 #if MSDOS_COMPILER==WIN32C
81 #if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
93 if (SET_JUMP(read_label))
96 * We jumped here from intread.
103 sigprocmask(SIG_SETMASK, &mask, NULL);
119 #if MSDOS_COMPILER==DJGPPC
123 * Don't try reading from a TTY until a character is
124 * available, because that makes some background programs
125 * believe DOS is busy in a way that prevents those
126 * programs from working while "less" waits.
131 FD_SET(fd, &readfds);
132 if (select(fd+1, &readfds, 0, 0, 0) == -1)
136 n = read(fd, buf, len);
139 * This is a kludge to workaround a problem on some systems
140 * where terminating a remote tty connection causes read() to
141 * start returning 0 forever, instead of -1.
144 extern int ignore_eoi;
147 static int consecutive_nulls = 0;
151 consecutive_nulls = 0;
152 if (consecutive_nulls > 20)
162 * Certain values of errno indicate we should just retry the read.
164 #if MUST_DEFINE_ERRNO
182 * Interrupt a pending iread().
187 LONG_JUMP(read_label, 1);
191 * Return the current time.
207 * Local version of strerror, if not available from the system.
215 extern char *sys_errlist[];
219 return sys_errlist[err];
220 sprintf(buf, "Error %d", err);
223 return ("cannot open");
229 * errno_message: Return an error message based on the value of "errno".
232 errno_message(filename)
239 #if MUST_DEFINE_ERRNO
246 len = strlen(filename) + strlen(p) + 3;
247 m = (char *) ecalloc(len, sizeof(char));
248 SNPRINTF2(m, len, "%s: %s", filename, p);
252 /* #define HAVE_FLOAT 0 */
255 muldiv(val, num, den)
256 POSITION val, num, den;
259 double v = (((double) val) * num) / den;
260 return ((POSITION) (v + 0.5));
262 POSITION v = ((POSITION) val) * num;
266 return (POSITION) (v / den);
268 /* Above calculation overflows;
269 * use a method that is less precise but won't overflow. */
270 return (POSITION) (val / (den / num));
275 * Return the ratio of two POSITIONS, as a percentage.
276 * {{ Assumes a POSITION is a long int. }}
282 return (int) muldiv(num, (POSITION) 100, den);
286 * Return the specified percentage of a POSITION.
289 percent_pos(pos, percent, fraction)
294 /* Change percent (parts per 100) to perden (parts per NUM_FRAC_DENOM). */
295 POSITION perden = (percent * (NUM_FRAC_DENOM / 100)) + (fraction / 100);
299 return (POSITION) muldiv(pos, perden, (POSITION) NUM_FRAC_DENOM);
304 * strchr is used by regexp.c.
311 for ( ; *s != '\0'; s++)
322 memcpy(dst, src, len)
327 char *dstp = (char *) dst;
328 char *srcp = (char *) src;
331 for (i = 0; i < len; i++)
340 * This implements an ANSI-style intercept setup for Microware C 3.2
343 os9_signal(type, handler)
345 RETSIGTYPE (*handler)();
358 if (_gs_opt(f, &sgbuf) < 0)
360 return (sgbuf.sg_class == 0);