Note: This is an unofficial bindbc package, please don't contact Mike for help.

This project provides both static and dynamic bindings to the GnuTLS library. They are @nogc and nothrow compatible and can be compiled for compatibility with -betterC.

GnuTLS v3.6.15 was used to generate these bindings so it should be ABI v3.4.0 compatible.

This library source is licensed with BSL-1.0.

But for static binding, please note that GnuTLS itself is licensed in LGPLv2.1+ so these bindings must be used in a corresponding way.

By default, bindbc-gnutls is configured to compile as a dynamic binding that is not -betterC compatible. The dynamic binding has no link-time dependency on the GnuTLS library, so the GnuTLS shared library must be manually loaded at runtime. When configured as a static binding, there is a link-time dependency on the GnuTLS library (and it's Dane extension if needed); either the static library or the appropriate file for linking with shared libraries on your platform (see below).

When using DUB to manage your project, the static binding can be enabled via a DUB subConfiguration statement in your project's package file. -betterC compatibility is also enabled via subconfigurations.

To use GnuTLS, add bindbc-gnutls as a dependency to your project's package config file. For example, the following is configured to GnuTLS as a dynamic binding that is not -betterC compatible:

dependencies {
    "bindbc-gnutls": "~>1.0.0",
}

dependency "bindbc-gnutls" version="~>1.0.0"

By default, binding is compiled with symbols defined in GnuTLS v3.5.0. If symbols from higher versions are required, binding user must specify this with version directive (through compiler switch or dub file).

You can check what version the binding was compiled for using gnuTLSSupport constant.

Supported versions:

Note that some GnuTLS versions doesn't come with their own compiler version constant. It's because that library version haven't introduced API change and is compatible with previous version binding.

Use minimal required version to compile the library so newer ones can still be loaded although without the new API additions.

The dynamic binding requires no special configuration when using DUB to manage your project. There is no link-time dependency. At runtime, the GnuTLS shared library is required to be on the shared library search path of the user's system. On Windows, this is typically handled by distributing the GnuTLS DLL with your program. On other systems, it usually means the user must install the GnuTLS runtime library through a package manager.

To load the shared library, you need to call the loadGnuTLS function. This returns a member of the GnuTLSSupport enumeration (See the README for bindbc.loader for the error handling API):

• GnuTLSSupport.noLibrary indicating that the library failed to load (it couldn't be found)
• GnuTLSSupport.badLibrary indicating that one or more symbols in the library failed to load
• GnuTLSSupport.xxx indicating that GnuTLS has been successfully loaded in with a minimal required version.

Same applies to GnuTLS Dane, just use loadGnuTLS_Dane for that.

import core.stdc.stdio;
import bindbc.gnutls;
import loader = bindbc.loader.sharedlib;

auto res = loadGnuTLS();
if (res != LoadRes.loaded)
{
    printf("Error loading GnuTLS: %d\n", res);
    foreach(info; loader.errors)
    {
        printf("\t%s: %s\n", info.error, info.message);
    }
    assert(0);
}

The static binding has a link-time dependency on either the shared or the static GnuTLS library. On Windows, you can link with the static library or, to use the shared library (libgnutls-30.dll), with the import library. On other systems, you can link with either the static library or directly with the shared library. This requires the GnuTLS development package be installed on your system at compile time, either by compiling the GnuTLS source yourself, downloading the GnuTLS precompiled binaries for Windows, or installing via a system package manager. See the GnuTLS documentation for details.

When linking with the static library, there is no runtime dependency on GnuTLS. When linking with the shared library (or the import library on Windows), the runtime dependency is the same as the dynamic binding, the difference being that the shared library is no longer loaded manually---loading is handled automatically by the system when the program is launched.

Enabling the static binding can be done in two ways.

Pass the BindGnuTLS_Static version to the compiler and link with the appropriate library.

When using the compiler command line or a build system that doesn't support DUB, this is the only option. The -version=BindGnuTLS_Static option should be passed to the compiler when building your program. All of the required C libraries, as well as the bindbc-gnutls and bindbc-loader static libraries must also be passed to the compiler on the command line or via your build system's configuration (see tests/run.sh for some examples).

When using DUB, its versions directive is an option. For example, when using the static binding:

"dependencies": {
    "bindbc-gnutls": "~>1.0.0"
},
"versions": ["BindGnuTLS_Static"],
"libs": ["gnutls"]

dependency "bindbc-gnutls" version="~>1.0.0"
versions "BindGnuTLS_Static"
libs "gnutls"

Instead of using DUB's versions directive, a subConfiguration can be used. Enable the static subconfiguration for the bindbc-gnutls dependency:

"dependencies": {
    "bindbc-gnutls": "~>1.0.0"
},
"subConfigurations": {
    "bindbc-gnutls": "static"
},
"libs": ["gnutls"]

dependency "bindbc-gnutls" version="~>1.0.0"
subConfiguration "bindbc-gnutls" "static"
libs "gnutls"

This has the benefit that it completely excludes from the build any source modules related to the dynamic binding, i.e. they will never be passed to the compiler.

betterC support is enabled via the dynamicBC and staticBC subconfigurations, for dynamic and static bindings respectively. To enable the static binding with -betterC support:

"dependencies": {
    "bindbc-gnutls": "~>1.0.0"
},
"subConfigurations": {
    "bindbc-gnutls": "staticBC"
},
"libs": ["gnutls"]

dependency "bindbc-gnutls" version="~>1.0.0"
subConfiguration "bindbc-gnutls" "staticBC"
libs "gnutls"

When not using DUB to manage your project, first use DUB to compile the BindBC libraries with the dynamicBC or staticBC configuration, then pass -betterC to the compiler when building your project.