2.2 Add IOC instances to one application

Use one compiled application for several IOC instances. Each instance has its own startup directory under iocBoot; all use the same mouseApp code.

Complete Generate and run an IOC application first. In each command below, start in the directory containing tools/ and mouse/.

Choose the names

The generator uses these options:

Option	Selects	Example
`-p`	Application code and executable	`mouse`
`-l`	Location in the IOC name	`park`
`-d`	Device part of the IOC name	`woodmouse`
`-f`	Folder containing the application	`jeonglee_mouse`

Use ASCII letters, digits, and underscores for APPNAME, LOCATION, and FOLDER. Keep the application name’s case unchanged when adding an instance. Avoid ioc in application and location names.

Add another location

From the directory containing mouse/, generate a second instance:
```
bash tools/generate_ioc_structure.bash -l park -p mouse
```
park is outside the predefined facility locations. Enter y when asked to continue. The script creates mouse/iocBoot/iocpark-mouse/.
In the same parent directory, generate an instance with another device name:
```
bash tools/generate_ioc_structure.bash -l park -p mouse -d woodmouse
```
This creates mouse/iocBoot/iocpark-woodmouse/. The application code remains mouseApp, and both instances run the mouse executable.

In mouse/, build the application and prepare local diagnostic output:

cd mouse
make
mkdir -p epics-pvinfo/env epics-pvinfo/names
export TARGET_TOP="$PWD"

In mouse/, start the location instance:
```
cd iocBoot/iocpark-mouse
./st.cmd
```
Wait for iocRun: All initialization complete, then enter exit.
From iocpark-mouse/, start the device instance:
```
cd ../iocpark-woodmouse
./st.cmd
```
Wait for initialization and enter exit before continuing.

Use a different folder name

Return to the directory containing tools/ and mouse/. Copy the application to a destination that does not already exist:
```
cp -a mouse jeonglee_mouse
```
Keep the exact folder name jeonglee_mouse rather than substituting your own username so the remaining commands in this lesson match as shown.
Generate an instance in that folder:
```
bash tools/generate_ioc_structure.bash -l bts -p mouse -f jeonglee_mouse
```
-f selects the folder. -p mouse selects the application already in that folder. The instance is iocBoot/iocbts-mouse/.

In jeonglee_mouse/, rebuild the copied application:

cd jeonglee_mouse
make clean uninstall
make
mkdir -p epics-pvinfo/env epics-pvinfo/names
export TARGET_TOP="$PWD"
cd iocBoot/iocbts-mouse
./st.cmd

Wait for initialization, then enter exit.

Check an invalid application name

From the directory containing tools/ and jeonglee_mouse/, try changing the case of the existing application name:

bash tools/generate_ioc_structure.bash -l ar05 -p mOuse -f jeonglee_mouse

The generator must reject the mismatch between mOuse and mouse. A rejected command returns a nonzero status; it is the expected result of this exercise.

Verification

In mouse/, compare the startup files:

diff iocBoot/iochome-mouse/st.cmd iocBoot/iocpark-mouse/st.cmd
diff iocBoot/iochome-mouse/st.cmd iocBoot/iocpark-woodmouse/st.cmd

The IOC identity and location-dependent settings differ. diff returns status 1 when it finds differences; that status does not mean the generator failed.

The exercise is complete when all three added instances initialize and the wrong-case application name is rejected. To add a fourth location, repeat the generator with -l lab -p mouse, build, and run its startup.