ttyin.c revision 128345
1/* 2 * Copyright (C) 1984-2002 Mark Nudelman 3 * 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. 6 * 7 * For more information about less, or for information on how to 8 * contact the author, see the README file. 9 */ 10 11 12/* 13 * Routines dealing with getting input from the keyboard (i.e. from the user). 14 */ 15 16#include "less.h" 17#if OS2 18#include "cmd.h" 19#include "pckeys.h" 20#endif 21#if MSDOS_COMPILER==WIN32C 22#include "windows.h" 23extern char WIN32getch(); 24static DWORD console_mode; 25#endif 26 27public int tty; 28extern int sigs; 29 30/* 31 * Open keyboard for input. 32 */ 33 public void 34open_getchr() 35{ 36#if MSDOS_COMPILER==WIN32C 37 /* Need this to let child processes inherit our console handle */ 38 SECURITY_ATTRIBUTES sa; 39 memset(&sa, 0, sizeof(SECURITY_ATTRIBUTES)); 40 sa.nLength = sizeof(SECURITY_ATTRIBUTES); 41 sa.bInheritHandle = TRUE; 42 tty = (int) CreateFile("CONIN$", GENERIC_READ, 43 FILE_SHARE_READ, &sa, 44 OPEN_EXISTING, 0L, NULL); 45 GetConsoleMode((HANDLE)tty, &console_mode); 46 /* Make sure we get Ctrl+C events. */ 47 SetConsoleMode((HANDLE)tty, ENABLE_PROCESSED_INPUT); 48#else 49#if MSDOS_COMPILER 50 extern int fd0; 51 /* 52 * Open a new handle to CON: in binary mode 53 * for unbuffered keyboard read. 54 */ 55 fd0 = dup(0); 56 close(0); 57 tty = open("CON", OPEN_READ); 58#if MSDOS_COMPILER==DJGPPC 59 /* 60 * Setting stdin to binary causes Ctrl-C to not 61 * raise SIGINT. We must undo that side-effect. 62 */ 63 (void) __djgpp_set_ctrl_c(1); 64#endif 65#else 66 /* 67 * Try /dev/tty. 68 * If that doesn't work, use file descriptor 2, 69 * which in Unix is usually attached to the screen, 70 * but also usually lets you read from the keyboard. 71 */ 72#if OS2 73 /* The __open() system call translates "/dev/tty" to "con". */ 74 tty = __open("/dev/tty", OPEN_READ); 75#else 76 tty = open("/dev/tty", OPEN_READ); 77#endif 78 if (tty < 0) 79 tty = 2; 80#endif 81#endif 82} 83 84/* 85 * Close the keyboard. 86 */ 87 public void 88close_getchr() 89{ 90#if MSDOS_COMPILER==WIN32C 91 SetConsoleMode((HANDLE)tty, console_mode); 92 CloseHandle((HANDLE)tty); 93#endif 94} 95 96/* 97 * Get a character from the keyboard. 98 */ 99 public int 100getchr() 101{ 102 char c; 103 int result; 104 105 do 106 { 107#if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC 108 /* 109 * In raw read, we don't see ^C so look here for it. 110 */ 111 flush(); 112#if MSDOS_COMPILER==WIN32C 113 if (ABORT_SIGS()) 114 return (READ_INTR); 115 c = WIN32getch(tty); 116#else 117 c = getch(); 118#endif 119 result = 1; 120 if (c == '\003') 121 return (READ_INTR); 122#else 123 result = iread(tty, &c, sizeof(char)); 124 if (result == READ_INTR) 125 return (READ_INTR); 126 if (result < 0) 127 { 128 /* 129 * Don't call error() here, 130 * because error calls getchr! 131 */ 132 quit(QUIT_ERROR); 133 } 134#endif 135 /* 136 * Various parts of the program cannot handle 137 * an input character of '\0'. 138 * If a '\0' was actually typed, convert it to '\340' here. 139 */ 140 if (c == '\0') 141 c = '\340'; 142 } while (result != 1); 143 144 return (c & 0377); 145} 146