1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 1997 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* Copyright (c) 1988 AT&T */ 28 /* All Rights Reserved */ 29 30 /* 31 * University Copyright- Copyright (c) 1982, 1986, 1988 32 * The Regents of the University of California 33 * All Rights Reserved 34 * 35 * University Acknowledgment- Portions of this document are derived from 36 * software developed by the University of California, Berkeley, and its 37 * contributors. 38 */ 39 40 #pragma ident "%Z%%M% %I% %E% SMI" 41 42 /*LINTLIBRARY*/ 43 44 #include <unistd.h> 45 #include <sys/types.h> 46 #include "curses_inc.h" 47 48 /* 49 * Set the file descriptor for typeahead checks to fd. fd can be -1 50 * to disable the checking. 51 */ 52 53 int 54 typeahead(int fd) 55 { 56 #ifdef SYSV 57 /* 58 * Doing fcntls before and after each typeahead check 59 * read is a serious problem on the 3b2. Profiling 60 * results indicated that a simple program(edit.c from 61 * "The New Curses and Terminfo Package") was spending 62 * 9.2% of the time in fcntl(). 63 */ 64 65 #include <fcntl.h> 66 int savefd = cur_term->_check_fd; 67 68 /* Close the previous duped file descriptor. */ 69 if (savefd >= 0) 70 (void) close(savefd); 71 72 /* 73 * Duplicate the file descriptor so we have one to play with. 74 * We cannot use dup(2), unfortunately, so we do typeahead checking 75 * on terminals only. Besides, if typeahead is done when input is 76 * coming from a file, nothing would EVER get drawn on the screen! 77 */ 78 79 /* MODIFIED: DRS 3/26/89 */ 80 81 /* 82 * a couple of notes by DRS: first, a new file descriptor is 83 * required, since O_NDELAY must be set. calling fcntl() or dup() 84 * would provide a new file descriptor, but NOT a new file pointer 85 * for the open file (by file pointer, i mean a unix kernal file 86 * ptr). if a new underlying unix file ptr. is not allocated, 87 * setting O_NDELAY will cause all normal terminal i/o to return 88 * prematurely without blocking. 89 * 90 * second, the call to ttyname is NOT necessary, /dev/tty can be 91 * used instead. calling ttyname is quite expensive -- especially 92 * for large /dev directories. 93 * 94 * note also that the code for the '#else' clause will not work 95 * since the new file descriptor MUST have O_NDELAY set for the 96 * rest of libcurses code to function properly. 97 * 98 * 4/24/89: modified to set the close on exec() flag of the newly 99 * opened file descriptor 100 */ 101 102 /* 103 * cur_term->_check_fd = (tty = ttyname(fd)) ? 104 * open(tty, O_RDONLY | O_NDELAY) : -1; 105 */ 106 if (isatty(fd)) { 107 if ((cur_term->_check_fd = open("/dev/tty", O_RDONLY | 108 O_NDELAY)) >= 0) 109 (void) fcntl(cur_term->_check_fd, F_SETFD, 1); 110 } else 111 cur_term->_check_fd = -1; 112 113 #else /* SYSV */ 114 int savefd = cur_term->_check_fd; 115 /* Only do typeahead checking if the input is a tty. */ 116 if (isatty(fd)) 117 cur_term->_check_fd = fd; 118 else 119 cur_term->_check_fd = -1; 120 #endif /* SYSV */ 121 return (savefd); 122 } 123