Directory structure for GMI apps

Platform-specific rules need to be considered when deploying on iOS devices (GMI).

The application sandbox

On iOS devices, program interactions with the file system are limited to the directories inside the app's sandbox.

Directory structure for a GMI application

Inside its application sandbox, an iOS app uses the following directory structure:
|-- main.42m                            --
|-- *.42m                                 |
|-- *.42f                                 |
|-- fglprofile                            |
|   ...                                   |
|-- defaults/*.42s                        |
|-- de/                                   | Program files
|   |-- *.42s                             |
|-- fr/                                   |
|   |-- *.42s                             |
|-- zh/                                   |
|   |-- *.42s                             |
|-- ... other resource files/dirs ...     |
|   ...                                   |
|-- webcomponents                         |
|   |-- component-type                    |
|       |-- component-type.html           |
|       |-- other-web-comp-resource       |
|   ...                                 --

|-- ... writable app files ...
|-- ... temporary files ...


Program files directory (appdir)

Application program files (.42m, .42f, as well as other program resources) need to be deployed in the appdir directory.


On iOS, the application program directory is read-only. Only the "Documents" directory is writable.

The program files directory can be found in programs with the base.Application.getProgramDir method.

The FGLAPPDIR environment variable is automatically set to the appdir directory.

Program name (MAIN)

When deploying on mobile devices, the name of the program file must be main.42m or main.42r.

When using the command-line app build scripts, the name of the program file must be main.42?. When using Genero Studio, the packaging script takes care of renaming this file, if you have not named it main.

As with other program files, the "MAIN" module must be located under the appdir application program directory.

Working directory

The current working directory for an iOS application is typically a writable "Documents" directory, in the private folder of the app. For example, the path to the working directory can be "/private/var/mobile/.../Documents".

The current working directory can be found in program with the os.Path.pwd method.

File access without an absolute path will be relative to the current working directory.

Files that need to be writable (such as SQLite database files) must be created or copied from the program files directory into the working directory. Copy must be done by the app at first execution, by using base.Application.getProgramDir, to find the program files directory, and os.Path.pwd(), to find the working directory.

Temporary directory (tmpdir)

A temporary directory is available for the application.

In order to find the temporary directory for the app, use the standard.feInfo front call, with the "dataDirectory" parameter.

To create a temporary file name, use the os.Path.makeTempName() method.

Language directories for localized strings

When the app starts, the appropriate .42s string files will be loaded from the directory corresponding to the current language settings of the mobile device. String files to be loaded can be defined in the app's fglprofile, or you can use the main program name to avoid fglprofile settings.

For each language supported by your application, a directory must exist under appdir, with a name including the locale codes. Default string files (in English for example) can be provided under appdir/defaults, in case the regional settings of the device do not match one of the locale directories of the app, otherwise the application will stop with error -8006.

For example:

For more details, see Localized string files on mobile devices.

Deploying a custom fglprofile file

If you need to set fglprofile entries for your mobile application, create a file with the name fglprofile, and deploy it under the appdir directory, along with the other program files.

See Understanding FGLPROFILE for more details about fglprofile settings.

Creating the initial database file

When a mobile application starts for the first time, it typically creates a new database, or copies a existing database template file from the appdir program file directory (base.Application.getProgramDir) to the working directory (os.Path.pwd).

For more details about database creation on mobile devices, see Creating a database from programs.