# Understand Solutions, Projects, and Configurations

The Microsoft Visual Studio* IDE consists of one or more projects contained within a solution. A solution can contain multiple projects. If you have several Fortran applications that do different calculations but are related, you can store all the individual projects in a single solution. Along with a solution file (.sln), the IDE creates a solution user options (.suo) file for storing IDE customization.

The following table summarizes the files created by Microsoft Visual Studio when a new project is created:

File | Extension | Description
--- | --- | ---
Project Solution file | .sln | Stores solution information, including the projects and items in the solution and their locations on disk.
Project file | .vfproj .vcxproj | Contains information used to build a single project or sub-project.
Solution options file | .suo | Contains IDE customization for the solution, based on the selected options.

### CAUTION

- Directly modifying these files with a text editor is not supported.
- Before opening Compaq* Visual Fortran 6.0 projects or Intel® Visual Fortran 7.x projects in Microsoft Visual Studio, review the guidelines listed in Convert and Copy Projects.

Each project can specify one or more configurations to build from its source files. A configuration specifies such information as the type of application to build, the platform it runs on, and the tool settings to use when building. Having multiple configurations extends the scope of a project, but maintains a consistent source code base to work with.

Microsoft Visual Studio automatically creates Debug and Release (also known as Retail) configurations when a new project is started. The default configuration is the Debug configuration. To specify the current configuration, select Configuration Manager from the Build menu.

Specify build options in the Project > Properties dialog box, for one of the following:

- For all configurations (project-wide).

- For certain configurations (per configuration).

- For certain files (per file).

For example, specify compiler optimizations for all general configurations, but turn them off for certain configurations or certain files.

Once the files in the project are specified and the configurations for your project build are set, including the tool settings, build the project with the commands on the Build menu.

### Note

For a multiple-project solution, make sure that the executable project is designated as the startup project (shown in bold in the Solution Explorer view). To modify the startup project, right-click on the project and select Set as StartUp Project.
Parent topic: Use Microsoft Visual Studio

## See Also

Convert and Copy Projects