OVMS3-idf/examples/system/cpp_exceptions/README.md
2019-05-21 09:09:01 +02:00

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# Example: C++ exception handling
(See the README.md file in the upper level 'examples' directory for more information about examples.)
This example demonstrates usage of C++ exceptions in ESP-IDF.
By default, C++ exceptions support is disabled in ESP-IDF. It can be enabled using `CONFIG_COMPILER_CXX_EXCEPTIONS` configuration option.
In this example, `sdkconfig.defaults` file sets `CONFIG_COMPILER_CXX_EXCEPTIONS` option. This enables both compile time support (`-fexceptions` compiler flag) and run-time support for C++ exception handling.
Example source code declares a class which can throw exception from the constructor, depending on the argument. It illustrates that exceptions can be thrown and caught using standard C++ facilities.
## How to use example
### Configure the project
Run `make menuconfig` and set serial port under Serial Flasher Options.
### Build and Flash
Build the project and flash it to the board, then run monitor tool to view serial output:
```
make -j4 flash monitor
```
(To exit the serial monitor, type ``Ctrl-]``.)
See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
## Example Output
```
app_main starting
In constructor, arg=42
In constructor, arg=0
In destructor, m_arg=42
Exception caught: Exception in constructor
app_main done
```