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DMD Compiler for OSX

Requirements and Downloads

  1. Download D Compiler
  2. Mac OS X Lion (10.7) or later
  3. Xcode


D runtime library source
D compiler front end source under dual (GPL and Artistic) license
Sample D programs
D symbol demangler
D manual lookup tool
D compiler executable
Global compiler settings (copy to /etc/dmd.conf)
D's package manager
Mach-O file dumper
D source code minimizer
Mach-O file disassembler
D build tool for script-like D code execution
Simple command line shell
D runtime library (copy to /usr/local/lib/lib)


  • Put the dmd zip file into your home directory, and unzip it:
    where VERSION is the particular version of the zip file.
  • It will create a ~/dmd2 directory with all the files in it. All the tools are command line tools, which means they are run from a console window.
  • Verify that this works by creating hello.d in your home directory with these contents:
    import std.stdio;
    void main()
        writeln("hello world!");
    and compile and run it with:
    dmd2/osx/bin/dmd hello
    and it should print:
    hello world!
  • To install a global copy:
  • Copy binaries to /usr/local/bin:
    sudo cp dmd2/osx/bin/{dmd,dumpobj,obj2asm,shell,rdmd} /usr/local/bin
    sudo cp dmd2/osx/bin/dmdx.conf /usr/local/bin/dmd.conf
  • Copy the library to /usr/local/lib:
    sudo cp dmd2/osx/lib/lib /usr/local/lib
  • Compiler Arguments and Switches

    dmd files... -switches...
    File Extensions
    Extension File Type
    none D source files
    .d D source files
    .dd Ddoc source files
    .di D interface files
    .o Object files to link in
    .a Object code libraries to search
    If cmdfile is an environment variable, read the compiler arguments and switches from the value of that variable. Otherwise, read compiler arguments and switches from the text file cmdfile. The file may contain single-line comments starting with the hash symbol (#).
    generate code for all template instantiations
    Adjusts the compiler to implement D as a better C:
    • Predefines D_betterC version.
    • Assert Expressions, when they fail, call the C runtime library assert failure function rather than a function in the D runtime.
    • Array overflows call the C runtime library assert failure function rather than a function in the D runtime.
    • Final switch errors call the C runtime library assert failure function rather than a function in the D runtime.
    • Does not automatically link with phobos runtime library.
    • Does not generate Dwarf eh_frame with full unwinding information, i.e. exception tables are not inserted into eh_frame.
    • Module constructors and destructors are not generated meaning that static and shared static constructors and destructors will not get called.
    • ModuleInfo is not generated.
    • TypeInfo instances will not be generated for structs.
    controls if bounds checking is enabled.
    • on: Bounds checks are enabled for all code. This is the default.
    • safeonly: Bounds checks are enabled only in @safe code. This is the default for -release builds.
    • off: Bounds checks are disabled completely (even in @safe code). This option should be used with caution and as a last resort to improve performance. Confirm turning off @safe bounds checks is worthwhile by benchmarking.
    compile only, do not link
    Show colored console output. The default depends on terminal capabilities.
    • on: always use colored output. Same as -color
    • off: never use colored output.
    -conf=path use config file at path

    Perform code coverage analysis and generate .lst file with report.

    dmd -cov -unittest myprog.d
    Perform code coverage analysis, generate .lst file with report, and error at runtime if code coverage is less than nnn% of the executable lines. This can be integrated into the build test process to ensure minimum unit test coverage.

    Generate documentation from source.

    Note: mind the security considerations.

    write documentation file to docdir directory. -op can be used if the original package hierarchy should be retained
    write documentation file to filename
    Silently allow deprecated features and use of symbols with deprecated attributes.
    treat use of deprecated features and attributes as warnings (this is the default)
    treat use of deprecated features and attributes as errors
    compile in debug code
    compile in debug level <= level
    compile in debug identifier ident
    Link in libname as the default library when compiling for symbolic debugging instead of lib. If libname is not supplied, then no default library is linked in.
    Link in libname as the default library when not compiling for symbolic debugging instead of lib. If libname is not supplied, then no default library is linked in.
    Without filename, print module dependencies (imports/file/version/debug/lib). With filename, write module dependencies as text to filename (only imports).
    implement (experimental)
    generate Position Independent Code (which is used for building shared libraries). This is always on for OSX.
    add symbolic debug info in Dwarf format for debuggers such as gdb
    backwards compatibility option for the the -g switch
    always generate standard stack frame
    add stack stomp code
    generate D interface file
    write D interface file to dir directory. -op can be used if the original package hierarchy should be retained
    write D interface file to filename
    print brief help to console
    where to look for imports. path is a ; separated list of paths. Multiple -I's can be used, and the paths are searched in the same order.
    ignore unsupported pragmas
    inline expand functions at the discretion of the compiler. This can improve performance, at the expense of making it more difficult to use a debugger on it.
    where to look for files for ImportExpressions. This switch is required in order to use ImportExpressions. path is a ; separated list of paths. Multiple -J's can be used, and the paths are searched in the same order.
    pass linkerflag to the linker, for example, -L-M
    generate library file as output instead of object file(s). All compiled source files, as well as object files and library files specified on the command line, are inserted into the output library. Compiled source modules may be partitioned into several object modules to improve granularity. The name of the library is taken from the name of the first source module to be compiled. This name can be overridden with the -of switch.
    compile a 32 bit executable. This is the default for the 32 bit dmd.
    compile a 64 bit executable. This is the default for the 64 bit dmd.
    Add a default main() function when compiling. This is useful when unittesting a library, as it enables running the unittests in a library without having to manually define an entry-point function.
    open browser specified by the BROWSER environment variable on this page. If BROWSER is undefined, Safari is assumed.
    generate a .map file
    Set the target architecture for code generation, where:
    list alternatives
    the minimum architecture for the target platform (default)
    generate AVX instructions instead of SSE instructions for vector and floating point operations. Not available for 32 bit memory models other than OSX32.
    use the architecture the compiler is running on
    Use path/filename as the source file for package.module. This is used when the source file path and names are not the same as the package and module hierarchy. The rightmost components of the path/filename and package.module can be omitted if they are the same.
    turns off all array bounds checking, even for safe functions. Deprecated (use -boundscheck=off instead).
    Optimize generated code. For fastest executables, compile with the -O -release -inline -boundscheck=off switches together.
    Suppress generation of object file. Useful in conjuction with -D or -H flags.
    write object files relative to directory objdir instead of to the current directory. -op can be used if the original package hierarchy should be retained
    Set output file name to filename in the output directory. The output file can be an object file, executable file, or library file depending on the other switches.
    normally the path for .d source files is stripped off when generating an object, interface, or Ddoc file name. -op will leave it on.
    profile the runtime performance of the generated code.
    • gc: Instrument calls to memory allocation and write a report to the file profilegc.log upon program termination.
    compile release version, which means not emitting run-time checks for contracts and asserts. Array bounds checking is not done for system and trusted functions, and assertion failures are undefined behaviour.
    -run srcfile args... compile
    link, and run the program srcfile with the rest of the command line, args..., as the arguments to the program. No .o or executable file is left behind.
    generate shared library
    show additional info about language change identified by id
    list all language changes
    compile in unittest code, turns on asserts, and sets the unittest version identifier
    print character (column) numbers in diagnostics
    limit the number of error messages (0 means unlimited)
    compile in version level >= level
    compile in version identifier ident
    list all gc allocations including hidden ones
    print informational messages identifying variables defaulting to thread local storage. Handy for migrating to shared model.
    enable warnings
    enable informational warnings (i.e. compilation still proceeds normally)
    generate JSON file
    write JSON file to filename


    Linking is done directly by the dmd compiler after a successful compile. To prevent dmd from running the linker, use the -c switch.

    The actual linking is done by running gcc. This ensures compatibility with modules compiled with gcc.

    Environment Variables

    The D compiler dmd uses the following environment variables:

    dmd normally runs the linker by looking for gcc along the PATH. To use a specific linker instead, set the CC environment variable to it. For example:
    set CC=gcc
    This sets the browser used to open the manual page with the -man switch. It defaults to x-www-browser.
    The value of DFLAGS is treated as if it were appended to the command line to dmd.

    dmd.conf Initialization File

    The dmd file dmd.conf is the same as sc.ini for Windows, it's just that the file has a different name, enabling a setup common to both Windows and this system to be created without having to re-edit the file.

    dmd will look for the initialization file dmd.conf in the following sequence of directories:

    1. current working directory
    2. directory specified by the HOME environment variable
    3. directory dmd resides in
    4. /etc/

    If found, environment variable settings in the file will override any existing settings. This is handy to make dmd independent of programs with conflicting use of environment variables.

    Environment variables follow the [Environment] section heading, in NAME=value pairs. The NAMEs are treated as upper case. Comments are lines that start with ;. For example:

    ; dmd.conf file for dmd
    ; Names enclosed by %% are searched for in the existing environment
    ; and inserted. The special name %@P% is replaced with the path
    ; to this file.
    DFLAGS=-I%@P%/../src/phobos -I%@P%/../src/druntime/import

    Differences between Windows and Linux versions

    D Interface Files

    When an import declaration is processed in a D source file, the compiler searches for the D source file corresponding to the import, and processes that source file to extract the information needed from it. Alternatively, the compiler can instead look for a corresponding D interface file. A D interface file contains only what an import of the module needs, rather than the whole implementation of that module.

    The advantages of using a D interface file for imports rather than a D source file are:

    D interface files can be created by the compiler from a D source file by using the -H switch to the compiler. D interface files have the .di file extension. When the compiler resolves an import declaration, it first looks for a .di D interface file, then it looks for a D source file.

    D interface files bear some analogous similarities to C++ header files. But they are not required in the way that C++ header files are, and they are not part of the D language. They are a feature of the compiler, and serve only as an optimization of the build process.

    Building Executables

    dmd can build an executable much faster if as many of the source files as possible are put on the command line.

    Another advantage to putting multiple source files on the same invocation of dmd is that dmd will be able to do some level of cross-module optimizations, such as function inlining across modules.

    Building Libraries

    There are three ways to build a library. For example, given foo.d and bar.d which are to be compiled, and existing object file abc.o and existing library def.a which are all to be combined into a library foo.a:

    1. Compile modules separately and then run the librarian on them:
      dmd -c foo.d
      dmd -c bar.d
      rm -f foo.a
      ar -r foo.a foo.o bar.o abc.o def.a
      rm foo.o bar.o
      This option is typical when using a makefile to avoid compiling modules that have already been compiled.
    2. Compile modules together and then run the librarian on them:
      dmd -c foo.d bar.d
      rm -f foo.a
      ar -r foo.a foo.o bar.o abc.o def.a
      rm foo.o bar.o
    3. Use dmd to compile and build library in one operation:
      dmd -lib foo.d bar.d abc.o def.a
      No object files are written to disk, it's all done in memory. Using -lib also has the advantage that modules may be compiled into multiple object files rather than exactly one per module. This improves granularity of the library without having to break up the modules.

    Compiling dmd

    Complete source code is provided to build the compiler. Follow these steps:

    cd ~/dmd2/src/dmd
    make -f posix.mak

    Compiling Phobos

    Complete source code is provided to build Phobos, the D runtime library. Follow these steps:

    cd ~/dmd2/src/druntime
    make -f posix.mak DMD=~/dmd2/osx/bin/dmd
    cd ../phobos
    make -f posix.mak DMD=~/dmd2/osx/bin/dmd