/* * have_offscl - determine if we have a scalar off_t element * * Copyright (C) 1999,2021 Landon Curt Noll * * Calc is open software; you can redistribute it and/or modify it under * the terms of the version 2.1 of the GNU Lesser General Public License * as published by the Free Software Foundation. * * Calc is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General * Public License for more details. * * A copy of version 2.1 of the GNU Lesser General Public License is * distributed with calc under the filename COPYING-LGPL. You should have * received a copy with calc; if not, write to Free Software Foundation, Inc. * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * * Under source code control: 1996/07/13 12:57:22 * File existed as early as: 1996 * * chongo /\oo/\ http://www.isthe.com/chongo/ * Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/ */ /* * usage: * have_offscl * * On some systems, off_t is a scalar value on which one can perform * arithmetic operations, assignments and comparisons. On some systems * off_t is some sort of union or struct which must be converted into * a ZVALUE in order to perform arithmetic operations, assignments and * comparisons. * * * This prog outputs several defines: * * HAVE_OFF_T_SCALAR * defined ==> OK to perform arithmetic ops, = and comparisons * undefined ==> convert to ZVALUE first */ #include #include #include #include "have_unistd.h" #if defined(HAVE_UNISTD_H) #include #endif #include "banned.h" /* include after system header <> includes */ int main(void) { #if !defined(OFF_T_NON_SCALAR) off_t value; /* an off_t to perform arithmetic on */ off_t value2; /* an off_t to perform arithmetic on */ /* * do some math opts on an off_t */ value = (off_t)getpid(); value2 = (off_t)-1; if (value > (off_t)1) { --value; } #if !defined(_WIN32) && !defined(_WIN64) if (value <= (off_t)getppid()) { --value; } #endif if (value == value2) { value += value2; } value <<= 1; if (!value) { printf("/* something for the off_t to do */\n"); } /* * report off_t as a scalar */ printf("#undef HAVE_OFF_T_SCALAR\n"); printf("#define HAVE_OFF_T_SCALAR /* off_t is a simple value */\n"); #else printf("#undef HAVE_OFF_T_SCALAR /* off_t is not a simple value */\n"); #endif /* exit(0); */ return 0; }