How to use the command `dmd` (with examples)

The dmd command is the Official D compiler that allows developers to compile D source files and generate code for template instantiations. It also provides options to control bounds checking, list information on available checks, and turn on colored console output.

Use case 1: Build a D source file

Code:

dmd path/to/source.d

Motivation: The dmd command is used to build D source files. By providing the path to the source file, the command will compile the source code and generate an executable program or library.

Explanation:

• dmd: The command itself.
• path/to/source.d: The path to the D source file that needs to be compiled.

Example output: If the compilation is successful, the command will generate an executable file named source in the current directory.

Use case 2: Generate code for all template instantiations

Code:

dmd -allinst

Motivation: When working with templates in D, it can be useful to generate code for all template instantiations. This can help in debugging and understanding how the code is being generated.

Explanation:

• -allinst: This argument tells the dmd command to generate code for all template instantiations in the source file.

Example output: The command will compile the source code and generate code for all template instantiations, resulting in additional object files or executables depending on the source file.

Use case 3: Control bounds checking

Code:

dmd -boundscheck=on|safeonly|off

Motivation: Bounds checking is a feature in D that helps detect array index out-of-bounds errors at runtime. By controlling bounds checking, developers can choose to enable or disable this feature based on their needs.

Explanation:

• -boundscheck=on|safeonly|off: This argument allows developers to control the bounds checking feature.
  • on: Enables bounds checking, which performs runtime checks for array index out-of-bounds errors.
  • safeonly: Enables bounds checking only for @safe code, disabling it for @trusted and @system code.
  • off: Disables bounds checking completely.

Example output: Depending on the value provided for the -boundscheck argument, the command will either enable or disable the bounds checking feature during compilation.

Use case 4: List information on all available checks

Code:

dmd -check=h|help|?

Motivation: The dmd command provides various checks that can be enabled or disabled during compilation. Listing information on all available checks can help developers understand and choose the appropriate checks for their code.

Explanation:

• -check=h|help|?: This argument lists information on all available checks that can be enabled or disabled during compilation.

Example output: When executing the command, it will display a description of the available checks, including their names and a brief explanation.

Use case 5: Turn on colored console output

Code:

dmd -color

Motivation: By default, the console output of the dmd command is not colored. Enabling colored console output can make it easier to read and understand the output of the compilation process.

Explanation:

• -color: This argument enables colored console output during the execution of the dmd command.

Example output: When executing the command with the -color argument, the console output will be displayed with colors, making it more visually appealing and easier to differentiate the different types of messages.

Conclusion:

In this article, we explored the various use cases of the dmd command. We learned how to build D source files, generate code for template instantiations, control bounds checking, list information on available checks, and turn on colored console output. By understanding these use cases, developers can effectively use the dmd command for their D programming needs.