1 /* Test for nonblocking read and write. 2 3 Copyright (C) 2011-2021 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <https://www.gnu.org/licenses/>. */ 17 18 /* A data block ought to be larger than the size of the in-kernel buffer. 19 Working values of SOCKET_DATA_BLOCK_SIZE, depending on kernel: 20 21 Platform SOCKET_DATA_BLOCK_SIZE 22 23 Linux >= 7350000 (depends on circumstances) 24 Linux/Android >= 1700000 (approx.) 25 FreeBSD >= 107521 26 OpenBSD >= 106430 (depends on circumstances) 27 Mac OS X >= 680000 (depends on circumstances) 28 AIX 5.1 >= 125713 29 AIX 7.1 >= 200000 (depends on circumstances) 30 HP-UX >= 114689 31 IRIX >= 61089 32 OSF/1 >= 122881 33 Solaris 7 >= 63000 (depends on circumstances) 34 Solaris 8 >= 49153 35 Solaris 9 >= 73729 36 Solaris 10 >= 98305 37 Solaris 11 2010-11 >= 73729 38 Cygwin 1.5.x >= 66294401 but then write() fails with ENOBUFS 39 Cygwin 1.7.x >= 163838 (depends on circumstances) 40 native Windows >= 66294401 41 */ 42 #define SOCKET_DATA_BLOCK_SIZE 1000000 43 44 /* On Linux, Mac OS X, Cygwin 1.5.x, native Windows, 45 sockets have very large buffers in the kernel, so that write() calls 46 succeed before the reader has started reading, even if fd is blocking 47 and the amount of data is larger than 1 MB. */ 48 #if defined __linux__ || defined __ANDROID__ || (defined __APPLE__ && defined __MACH__) || defined _WIN32 || defined __CYGWIN__ 49 # define SOCKET_HAS_LARGE_BUFFER 1 50 #else 51 # define SOCKET_HAS_LARGE_BUFFER 0 52 #endif