---
title: Release 0.37
short-description: Release notes for 0.37
...

# New features

## Mesontest

Mesontest is a new testing tool that allows you to run your tests in many different ways. As an example you can run tests multiple times:

    mesontest --repeat=1000 a_test

or with an arbitrary wrapper executable:

    mesontest --wrap='valgrind --tool=helgrind' a_test

or under `gdb`, 1000 times in a row. This is handy for tests that fail spuriously, as when the crash happens you are given the full GDB command line:

    mesontest --repeat=1000 --gdb a_test

## Mesonrewriter

Mesonrewriter is an experimental tool to manipulate your build definitions programmatically. It is not installed by default yet but those interested can run it from the source repository.

As an example, here is how you would add a source file to a build target:

    mesonrewriter add --target=program --filename=new_source.c

## Shared modules

The new `shared_module` function allows the creation of shared modules, that is, extension modules such as plugins that are meant to be used solely with `dlopen` rather than linking them to targets.

## Gnome module

- Detect required programs and print useful errors if missing

### gtkdoc

- Allow passing a list of directories to `src_dir` keyword argument
- Add `namespace` keyword argument
- Add `mode` keyword argument
- Fix `gtkdoc-scangobj` finding local libraries

### compile_resources

- Add `gresource_bundle` keyword argument to output `.gresource` files
- Add `export` and `install_header` keyword arguments
- Use depfile support available in GLib >= 2.52.0

## i18n module

- Add `merge_file()` function for creating translated files
- Add `preset` keyword argument to included common gettext flags
- Read languages from `LINGUAS` file

## LLVM IR compilation

Meson has long had support for compiling assembler (GAS) files. In this release we add support for compiling LLVM IR files in a similar way when building with the Clang compiler. Just add it to the list of files when creating a `library` or `executable` target like any other source file. No special handling is required:

```meson
executable('some-exe', 'main.c', 'asm-file.S', 'ir-file.ll')
```

As always, you can also mix LLVM IR files with C++, C, and Assembly (GAS) sources.

## ViM indent and syntax files

We now include filetype, indent, and syntax files for ViM [with the source tree](https://github.com/mesonbuild/meson/tree/master/data/syntax-highlighting/vim). Please file issues (or pull requests!) for enhancements or if you face any problems using them.

## Push URLs in .wrap files

[.wrap files](Using-the-WrapDB.md) for subprojects can now include a separate push URL to allow developers to push changes directly from a subproject git checkout.

## pkg-config dependencies

Meson now supports multiple version restrictions while searching for pkg-config dependencies.

```meson
# Just want a lower limit
dependency('zlib', version : '>1.2.1')
# Want both a lower and an upper limit
dependency('opencv', version : ['>=2.3.0', '<=3.1.0'])
# Want to exclude one specific broken version
dependency('foolite', version : ['>=3.12.1', '!=3.13.99'])
```

## Overriding more binaries with environment variables

You can now specify the binary to be used for the following tools by setting the corresponding environment variable

| Name | Environment variable |
| ---- | -------------------- |
| pkg-config | PKG_CONFIG     |
| readelf    | READELF        |
| nm         | NM             |

## Support for `localstatedir`

Similar to other options such as `bindir` and `datadir`, you can now specify the `localstatedir` for a project by passing `--localstatedir=dir` to `meson` or `-Dlocalstatedir=dir` to `mesonconf` after configuration. You can also access it from inside the `meson.build` file with `get_option('localstatedir')`.

## New compiler function `symbols_have_underscore_prefix`

Checks if the compiler prefixes an underscore to C global symbols with the default calling convention. This is useful when linking to compiled assembly code, or other code that does not have its C symbol mangling handled transparently by the compiler.

```meson
cc = meson.get_compiler('c')
conf = configuration_data()
if cc.symbols_have_underscore_prefix()
    conf.set('SYMBOLS_HAVE_UNDERSCORE', true)
endif
```

C symbol mangling is platform and architecture dependent, and a helper function is needed to detect it. For example, Windows 32-bit prefixes underscore, but 64-bit does not. Linux does not prefix an underscore but OS X does.

## Vala

GLib Resources compiled with [`gnome.compile_resources`](Gnome-module.md#compile_resources) that are added to the sources of a Vala build target will now cause the appropriate `--gresources` flag to be passed to the Vala compiler so you don't need to add that yourself to `vala_args:`.

## Improvements to install scripts

You can now pass arguments to install scripts added with [`meson.add_install_script()`](Reference-manual.md#meson-object). All arguments after the script name will be passed to the script.

The `MESON_INSTALL_DESTDIR_PREFIX` environment variable is now set when install scripts are called. This contains the values of the `DESTDIR` environment variable and the `prefix` option passed to Meson joined together. This is useful because both those are usually absolute paths, and joining absolute paths in a cross-platform way is tricky. [`os.path.join` in Python](https://docs.python.org/3/library/os.path.html#os.path.join) will discard all previous path segments when it encounters an absolute path, and simply concatenating them will not work on Windows where absolute paths begin with the drive letter.

## More install directories

Added new options `sbindir` and `infodir` that can be used for installation.