1# The atomic_ops library (`libatomic_ops`) 2 3IN NEW CODE, PLEASE USE C11 OR C++14 STANDARD ATOMICS INSTEAD OF THIS PACKAGE. 4 5This is version 7.6.12 of libatomic_ops. 6 7 8## Download 9 10You might find a more recent/stable version on the 11[Download](https://github.com/ivmai/libatomic_ops/wiki/Download) page, or 12[BDWGC site](http://www.hboehm.info/gc/). 13 14Also, the latest bug fixes and new features are available in the 15[development repository](https://github.com/ivmai/libatomic_ops). 16 17 18## Overview 19 20This package provides semi-portable access to hardware-provided 21atomic memory update operations on a number of architectures. These might 22allow you to write code: 23 24* That does more interesting things in signal handlers. 25 26* Makes more effective use of multiprocessors by allowing you to write 27 clever lock-free code. Note that such code is very difficult to get 28 right, and will unavoidably be less portable than lock-based code. It 29 is also not always faster than lock-based code. But it may occasionally 30 be a large performance win. 31 32* To experiment with new and much better thread programming paradigms, etc. 33 34For details and licensing restrictions see the files in the "doc" 35subdirectory. 36 37 38## Installation and Usage 39 40The configuration and build scripts for this package were generated by 41Automake/Autoconf. `./configure; make; sudo make install` in this 42directory should work. For a more customized build, see the output of 43`./configure --help`. To build it from the development repository, 44`./autogen.sh` should be executed first. 45 46Note that much of the content of this library is in the header files. 47However, two small libraries are built and installed: 48 49* `libatomic_ops.a` is a support library, which is not needed on some 50 platforms. This is intended to be usable, under some mild restrictions, 51 in free or proprietary code, as are all the header files. 52 See doc/LICENSING.txt. 53 54* `libatomic_ops_gpl.a` contains some higher level facilities. This code is 55 currently covered by the GPL. The contents currently correspond to 56 the headers `atomic_ops_stack.h` and `atomic_ops_malloc.h`. 57 58 59## Platform Specific Notes 60 61Win32/64: src/Makefile.msft contains a very simple Makefile for building 62and running tests and building the gpl library. The core `libatomic_ops` 63implementation is entirely in header files. 64 65HP-UX/PA-RISC: `aCC -Ae` won't work as a C compiler, since it doesn't support 66inline assembly code. Use cc. 67 68 69## Feedback, Contribution, Questions and Notifications 70 71Please address bug reports and new feature ideas to 72[GitHub issues](https://github.com/ivmai/libatomic_ops/issues). Before the 73submission please check that it has not been done yet by someone else. 74 75If you want to contribute, submit 76a [pull request](https://github.com/ivmai/libatomic_ops/pulls) to GitHub. 77 78If you need help, use 79[Stack Overflow](https://stackoverflow.com/questions/tagged/atomic-ops). 80Older questions on the site can be found by 81[this query](https://stackoverflow.com/search?q=atomic_ops). 82Older technical discussions are also available in `bdwgc` mailing list 83archive - it can be downloaded as a 84[compressed file](https://github.com/ivmai/bdwgc/files/1038163/bdwgc-mailing-list-archive-2017_04.tar.gz) 85or browsed at [Narkive](http://bdwgc.opendylan.narkive.com) (please search 86for _atomic_ keyword). 87 88To get new release announcements, subscribe to 89[RSS feed](https://github.com/ivmai/libatomic_ops/releases.atom). 90(To receive the notifications by email, a 3rd-party free service like 91[IFTTT RSS Feed](https://ifttt.com/feed) can be setup.) 92To be notified on all issues, please 93[watch](https://github.com/ivmai/libatomic_ops/watchers) the project on 94GitHub. 95 96 97## Copyright & Warranty 98 99 * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved. 100 * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved. 101 * Copyright (c) 1999-2011 Hewlett-Packard Development Company, L.P. 102 * Copyright (c) 2008-2021 Ivan Maidanski 103 104The file armcc/arm_v6.h is also 105 106 * Copyright (c) 2007 by NEC LE-IT. All rights reserved. 107 108The file gcc/avr32.h is 109 110 * Copyright (c) 2009 Bradley Smith <brad@brad-smith.co.uk> 111 112The file gcc/mips.h is 113 114 * Copyright (c) 2005, 2007 Thiemo Seufer <ths@networkno.de> 115 116The file gcc/sh.h is 117 118 * Copyright (c) 2009 by Takashi YOSHII. All rights reserved. 119 120See [LICENSING.txt](doc/LICENSING.txt) for the details. 121