1<!-- 2Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3 4SPDX-License-Identifier: curl 5--> 6 7# curl internals 8 9The canonical libcurl internals documentation is now in the [everything 10curl](https://everything.curl.dev/internals) book. This file lists supported 11versions of libs and build tools. 12 13## Portability 14 15 We write curl and libcurl to compile with C89 compilers on 32-bit and up 16 machines. Most of libcurl assumes more or less POSIX compliance but that is 17 not a requirement. 18 19 We write libcurl to build and work with lots of third party tools, and we 20 want it to remain functional and buildable with these and later versions 21 (older versions may still work but is not what we work hard to maintain): 22 23## Dependencies 24 25 We aim to support these or later versions. 26 27 - OpenSSL 0.9.7 28 - GnuTLS 3.1.10 29 - zlib 1.1.4 30 - libssh2 1.0 31 - c-ares 1.16.0 32 - libidn2 2.0.0 33 - wolfSSL 2.0.0 34 - OpenLDAP 2.0 35 - MIT Kerberos 1.2.4 36 - Heimdal ? 37 - nghttp2 1.15.0 38 - Winsock 2.2 (on Windows 95+ and Windows CE .NET 4.1+) 39 40## Build tools 41 42 When writing code (mostly for generating stuff included in release tarballs) 43 we use a few "build tools" and we make sure that we remain functional with 44 these versions: 45 46 - GNU Libtool 1.4.2 47 - GNU Autoconf 2.59 48 - GNU Automake 1.7 49 - GNU M4 1.4 50 - perl 5.8 51 - roffit 0.5 52 - cmake 3.7 53 54Library Symbols 55=============== 56 57 All symbols used internally in libcurl must use a `Curl_` prefix if they are 58 used in more than a single file. Single-file symbols must be made static. 59 Public ("exported") symbols must use a `curl_` prefix. Public API functions 60 are marked with `CURL_EXTERN` in the public header files so that all others 61 can be hidden on platforms where this is possible. 62
