bindbc-nng 0.0.1

bindbc-nng

Dynamic and static bindings to NNG (nanomsg-next-gen), compatible with -betterC, @nogc, and nothrow.

Usage

By default, bindbc-nng is configured to compile as a dynamic binding that is not -betterC compatible. The dynamic binding has no link-time dependency on the NNG library, so the NNG shared library must be manually loaded at runtime. When configured as a static binding, there is a link-time dependency on the NNG library---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 NNG, add bindbc-nng as a dependency to your project's package config file. For example, the following is configured to NNG as a dynamic binding that is not -betterC compatible:

dub.json

dependencies {
    "bindbc-nng": "~>0.0.1",
}

dub.sdl

dependency "bindbc-nng" version="~>0.0.1"

The dynamic binding

The dynamic binding requires no special configuration when using DUB to manage your project. There is no link-time dependency. At runtime, the NNG 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 NNG DLL with your program. On other systems, it usually means the user must install the NNG runtime library through a package manager.

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

• NngSupport.noLibrary indicating that the library failed to load (it couldn't be found)
• NngSupport.badLibrary indicating that one or more symbols in the library failed to load
• a member of NngSupport indicating a version number that matches the version of NNG that bindbc-nng was configured at compile-time to load.

import bindbc.nng;

/*
This version attempts to load the NNG shared library using well-known variations
of the library name for the host system.
*/
NngSupport ret = loadNNG();

// Handle error. For most use cases, its reasonable to use the the error handling API in
// bindbc-loader to retrieve error messages for logging and then abort. If necessary, it's
// possible to determine the root cause via the return value:

if(ret == NngSupport.noLibrary) {
// NNG shared library failed to load
}
else if(NngSupport.badLibrary) {
// One or more symbols failed to load. The likely cause is that the
// shared library is for a lower version than bindbc-nng was configured
// to load.

/*
This version attempts to load the NNG library using a user-supplied file name.
Usually, the name and/or path used will be platform specific, as in this example
which attempts to load `nng.dll` from the `libs` subdirectory, relative
to the executable, only on Windows.
*/
// version(Windows) loadNNG("libs/nng.dll")

No matter which version was configured, the successfully loaded version can be obtained via a call to loadedNNGVersion. It returns one of the following:

• NngSupport.noLibrary if loadNNG returned NngSupport.noLibrary
• NngSupport.badLibrary if loadNNG returned NngSupport.badLibrary and no version of NNG successfully loaded
• a member of NngSupport indicating the version of NNG that successfully loaded. When loadNNG returns NngSupport.badLibrary, this will be a version number lower than that configured at compile time. Otherwise, it will be the same as the manifest constant fiSupport.

The function isNNGLoaded returns true if any version of NNG was successfully loaded and false otherwise.

The static binding

The static binding has a link-time dependency on either the shared or the static NNG library. On Windows, you can link with the static library or, to use the shared library (nng.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 NNG development package be installed on your system at compile time, either by compiling the NNG source yourself, downloading the NNG precompiled binaries for Windows, or installing via a system package manager.

When linking with the static library, there is no runtime dependency on NNG. 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.

Via the compiler's -version switch or DUB's versions directive

Pass the BindNNG_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=BindNNG_Static option should be passed to the compiler when building your program. All of the required C libraries, as well as the bindbc-nng and bindbc-loader static libraries must also be passed to the compiler on the command line or via your build system's configuration.

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

dub.json

"dependencies": {
    "bindbc-nng": "~>0.0.1"
},
"versions": ["BindNNG_Static"],
"libs": ["nng"]

dub.sdl

dependency "bindbc-nng" version="~>0.0.1"
versions "BindNNG_Static"
libs "nng"

Via DUB subconfigurations

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

dub.json

"dependencies": {
    "bindbc-nng": "~>0.0.1"
},
"subConfigurations": {
    "bindbc-nng": "static"
},
"libs": ["nng"]

dub.sdl

dependency "bindbc-nng" version="~>0.0.1"
subConfiguration "bindbc-nng" "static"
libs "nng"

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

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

dub.json

"dependencies": {
    "bindbc-nng": "~>0.0.1"
},
"subConfigurations": {
    "bindbc-nng": "staticBC"
},
"libs": ["nng"]

dub.sdl

dependency "bindbc-nng" version="~>0.0.1"
subConfiguration "bindbc-nng" "staticBC"
libs "nng"

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.

License

Boost