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* Copyright (C) 1984-2000 Mark Nudelman
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* You may distribute under the terms of either the GNU General Public
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* License or the Less License, as specified in the README file.
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* For more information about less, or for information on how to
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* contact the author, see the README file.
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* Operating system dependent routines.
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* Most of the stuff in here is based on Unix, but an attempt
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* has been made to make things work on other operating systems.
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* This will sometimes result in a loss of functionality, unless
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* someone rewrites code specifically for the new operating system.
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* The makefile provides defines to decide whether various
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* Unix features are present.
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#define time_type time_t
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#define time_type long
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* BSD setjmp() saves (and longjmp() restores) the signal mask.
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* This costs a system call or two per setjmp(), so if possible we clear the
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* signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead.
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* On other systems, setjmp() doesn't affect the signal mask and so
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* _setjmp() does not exist; we just use setjmp().
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#if HAVE__SETJMP && HAVE_SIGSETMASK
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#define SET_JUMP _setjmp
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#define LONG_JUMP _longjmp
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#define SET_JUMP setjmp
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#define LONG_JUMP longjmp
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static jmp_buf read_label;
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* Like read() system call, but is deliberately interruptible.
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* A call to intread() from a signal handler will interrupt
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* any pending iread().
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#if MSDOS_COMPILER==WIN32C
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#if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
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if (SET_JUMP(read_label))
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* We jumped here from intread.
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sigprocmask(SIG_SETMASK, &mask, NULL);
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#if MSDOS_COMPILER==DJGPPC
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* Don't try reading from a TTY until a character is
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* available, because that makes some background programs
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* believe DOS is busy in a way that prevents those
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* programs from working while "less" waits.
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FD_SET(fd, &readfds);
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if (select(fd+1, &readfds, 0, 0, 0) == -1)
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n = read(fd, buf, len);
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* This is a kludge to workaround a problem on some systems
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* where terminating a remote tty connection causes read() to
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* start returning 0 forever, instead of -1.
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extern int ignore_eoi;
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static int consecutive_nulls = 0;
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consecutive_nulls = 0;
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if (consecutive_nulls > 20)
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* Interrupt a pending iread().
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LONG_JUMP(read_label, 1);
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* Return the current time.
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* Local version of strerror, if not available from the system.
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extern char *sys_errlist[];
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return sys_errlist[err];
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sprintf(buf, "Error %d", err);
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return ("cannot open");
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* errno_message: Return an error message based on the value of "errno".
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errno_message(filename)
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#if MUST_DEFINE_ERRNO
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m = (char *) ecalloc(strlen(filename) + strlen(p) + 3, sizeof(char));
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sprintf(m, "%s: %s", filename, p);
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* Return the ratio of two POSITIONS, as a percentage.
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* {{ Assumes a POSITION is a long int. }}
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POSITION num100 = num * 100;
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if (num100 / 100 == num)
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return (num100 / den);
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return (num / (den / 100));
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* Return the specified percentage of a POSITION.
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percent_pos(pos, percent)
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else if ((result100 = pos * percent) / percent == pos)
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return (result100 / 100);
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return (percent * (pos / 100));
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* strchr is used by regexp.c.
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for ( ; *s != '\0'; s++)
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memcpy(dst, src, len)
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char *dstp = (char *) dst;
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char *srcp = (char *) src;
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for (i = 0; i < len; i++)
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* This implements an ANSI-style intercept setup for Microware C 3.2
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os9_signal(type, handler)
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RETSIGTYPE (*handler)();
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if (_gs_opt(f, &sgbuf) < 0)
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return (sgbuf.sg_class == 0);