1 /* isatty() replacement. 2 Copyright (C) 2012-2014 Free Software Foundation, Inc. 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 3 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 16 17 #include <config.h> 18 19 /* Specification. */ 20 #include <unistd.h> 21 22 /* This replacement is enabled on native Windows. */ 23 24 #include <errno.h> 25 26 /* Get declarations of the Win32 API functions. */ 27 #define WIN32_LEAN_AND_MEAN 28 #include <windows.h> 29 30 #include "msvc-inval.h" 31 32 /* Get _get_osfhandle(). */ 33 #include "msvc-nothrow.h" 34 35 /* Optimized test whether a HANDLE refers to a console. 36 See <http://lists.gnu.org/archive/html/bug-gnulib/2009-08/msg00065.html>. */ 37 #define IsConsoleHandle(h) (((intptr_t) (h) & 3) == 3) 38 39 #if HAVE_MSVC_INVALID_PARAMETER_HANDLER 40 static int _isatty_nothrow(int fd)41_isatty_nothrow (int fd) 42 { 43 int result; 44 45 TRY_MSVC_INVAL 46 { 47 result = _isatty (fd); 48 } 49 CATCH_MSVC_INVAL 50 { 51 result = 0; 52 } 53 DONE_MSVC_INVAL; 54 55 return result; 56 } 57 #else 58 # define _isatty_nothrow _isatty 59 #endif 60 61 /* Determine whether FD refers to a console device. Return 1 if yes. 62 Return 0 and set errno if no. (ptsname_r relies on the errno value.) */ 63 int isatty(int fd)64isatty (int fd) 65 { 66 HANDLE h = (HANDLE) _get_osfhandle (fd); 67 if (h == INVALID_HANDLE_VALUE) 68 { 69 errno = EBADF; 70 return 0; 71 } 72 /* _isatty (fd) tests whether GetFileType of the handle is FILE_TYPE_CHAR. 73 But it does not set errno when it returns 0. */ 74 if (_isatty_nothrow (fd)) 75 { 76 if (IsConsoleHandle (h)) 77 return 1; 78 } 79 errno = ENOTTY; 80 return 0; 81 } 82