2 * Copyright (C) 1984-2002 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 about less, or for information on how to
8 * contact the author, see the README file.
13 * Operating system dependent routines.
15 * Most of the stuff in here is based on Unix, but an attempt
16 * has been made to make things work on other operating systems.
17 * This will sometimes result in a loss of functionality, unless
18 * someone rewrites code specifically for the new operating system.
20 * The makefile provides defines to decide whether various
21 * Unix features are present.
38 #define time_type time_t
40 #define time_type long
44 * BSD setjmp() saves (and longjmp() restores) the signal mask.
45 * This costs a system call or two per setjmp(), so if possible we clear the
46 * signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead.
47 * On other systems, setjmp() doesn't affect the signal mask and so
48 * _setjmp() does not exist; we just use setjmp().
50 #if HAVE__SETJMP && HAVE_SIGSETMASK
51 #define SET_JUMP _setjmp
52 #define LONG_JUMP _longjmp
54 #define SET_JUMP setjmp
55 #define LONG_JUMP longjmp
60 static jmp_buf read_label;
65 * Like read() system call, but is deliberately interruptible.
66 * A call to intread() from a signal handler will interrupt
67 * 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)
164 * Interrupt a pending iread().
169 LONG_JUMP(read_label, 1);
173 * Return the current time.
189 * Local version of strerror, if not available from the system.
197 extern char *sys_errlist[];
201 return sys_errlist[err];
202 sprintf(buf, "Error %d", err);
205 return ("cannot open");
211 * errno_message: Return an error message based on the value of "errno".
214 errno_message(filename)
220 #if MUST_DEFINE_ERRNO
227 m = (char *) ecalloc(strlen(filename) + strlen(p) + 3, sizeof(char));
228 sprintf(m, "%s: %s", filename, p);
233 * Return the ratio of two POSITIONS, as a percentage.
234 * {{ Assumes a POSITION is a long int. }}
240 POSITION num100 = num * 100;
242 if (num100 / 100 == num)
243 return (num100 / den);
245 return (num / (den / 100));
249 * Return the specified percentage of a POSITION.
252 percent_pos(pos, percent)
260 else if ((result100 = pos * percent) / percent == pos)
261 return (result100 / 100);
263 return (percent * (pos / 100));
268 * strchr is used by regexp.c.
275 for ( ; *s != '\0'; s++)
286 memcpy(dst, src, len)
291 char *dstp = (char *) dst;
292 char *srcp = (char *) src;
295 for (i = 0; i < len; i++)
304 * This implements an ANSI-style intercept setup for Microware C 3.2
307 os9_signal(type, handler)
309 RETSIGTYPE (*handler)();
322 if (_gs_opt(f, &sgbuf) < 0)
324 return (sgbuf.sg_class == 0);