mirror of https://github.com/c-ares/c-ares.git
... and did README.cares to contain a historic reason etc.pull/1/head
Daniel Stenberg
15 years ago
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This is c-ares, a forked version of the original ares. The original ares |
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README follows below, the c-ares specific details are in README.cares |
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==================================================================== |
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This is ares, an asynchronous resolver library. It is intended for |
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applications which need to perform DNS queries without blocking, or |
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need to perform multiple DNS queries in parallel. The primary |
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examples of such applications are servers which communicate with |
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multiple clients and programs with graphical user interfaces. |
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This library implementation is not especially portable to crufty old |
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systems like SunOS 4. It assumes a compiler which can handle ANSI C |
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syntax, a system malloc which properly handles realloc(NULL, foo) and |
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free(NULL), and a reasonably up-to-date <arpa/nameser.h>. |
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I have attempted to preserve the externally visible behavior of the |
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BIND resolver in nearly all respects. The API of the library is, of |
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course, very different from the synchronous BIND API; instead of |
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invoking a function like res_send() and getting a return value back |
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indicating the number of bytes in the response, you invoke a function |
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like ares_send() and give it a callback function to invoke when the |
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response arrives. You then have to select() on the file descriptors |
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indicated by ares_fds(), with a timeout given by ares_timeout(). You |
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call ares_process() when select() returns. |
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Some features are missing from the current version of ares, relative |
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to the BIND resolver: |
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* There is no IPV6 support. [not true for c-ares] |
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* There is no hostname verification. |
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* There is no logging of unexpected events. |
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* There is no debugging-oriented logging. |
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* There is no YP support. |
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libares requires an ANSI compiler to compile and use. To build the |
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library, just run "./configure" and "make". To install it, run "make |
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install". Run "./configure --help" to see a list of options you can |
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provide to configure to change how the library builds. libares has no |
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data files, so you can move the include file and library around freely |
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without leaving behind any dependencies on old paths. Building the |
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library will also build the "adig" program, a little toy for trying |
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out the library. It doesn't get installed. |
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libares is distributed at athena-dist.mit.edu:pub/ATHENA/ares. Please |
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send bug reports and comments to ghudson@mit.edu. |
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c-ares |
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====== |
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This is c-ares, an asynchronous resolver library. It is intended for |
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applications which need to perform DNS queries without blocking, or need to |
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perform multiple DNS queries in parallel. The primary examples of such |
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applications are servers which communicate with multiple clients and programs |
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with graphical user interfaces. |
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The full source code is available in the 'c-ares' release archives, and in a |
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git repository: http://github.com/bagder/c-ares |
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If you find bugs, correct flaws, have questions or have comments in general in |
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regard to c-ares (or by all means the original ares too), get in touch with us |
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on the c-ares mailing list: http://cool.haxx.se/mailman/listinfo/c-ares |
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c-ares is of course distributed under the same MIT-style license as the |
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original ares. |
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You'll find all c-ares details and news here: |
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http://c-ares.haxx.se/ |
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NOTES FOR C-ARES HACKERS |
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The following notes apply to c-ares version 1.7.0 and later. |
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* The distributed ares_build.h file is only intended to be used on systems |
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which can not run the also distributed configure script. |
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* The distributed ares_build.h file is generated as a copy of ares_build.h.dist |
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when the c-ares source code distribution archive file is originally created. |
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* If you check out from git on a non-configure platform, you must run the |
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appropriate buildconf* script to set up ares_build.h and other local files |
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before being able of compiling the library. |
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* On systems capable of running the configure script, the configure process |
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will overwrite the distributed ares_build.h file with one that is suitable |
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and specific to the library being configured and built, this new file is |
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generated from the ares_build.h.in template file. |
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* If you intend to distribute an already compiled c-ares library you _MUST_ |
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also distribute along with it the generated ares_build.h which has been |
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used to compile it. Otherwise the library will be of no use for the users of |
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the library that you have built. It is _your_ responsability to provide this |
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file. No one at the c-ares project can know how you have built the library. |
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* File ares_build.h includes platform and configuration dependent info, |
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and must not be modified by anyone. Configure script generates it for you. |
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* We cannot assume anything else but very basic compiler features being |
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present. While c-ares requires an ANSI C compiler to build, some of the |
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earlier ANSI compilers clearly can't deal with some preprocessor operators. |
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* Newlines must remain unix-style for older compilers' sake. |
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* Comments must be written in the old-style /* unnested C-fashion */ |
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