Using dynamic_cast / enabling RTTI

Projects Programming
1

I'm trying to use dynamic_cast to determine whether or not an instance of a class is implementing a certain interface.

when I try to compile this with standard board settings it results in the following error:

error: 'dynamic_cast' not permitted with -fno-rtti

But when I add -frtti to the compile options, and compiling goes great, the linker starts complaining:

Linking it all together ...
"C:\Users\Bas\AppData\Local\arduino15\packages\arduino\tools\avr-gcc\4.9.2-atmel
3.5.4-arduino2/bin/avr-g++" -w -Os -g -flto -fuse-linker-plugin -Wl,--gc-sections,--relax -mmcu=atmega2560 -o "C:\Users\Bas\AppData\Local\Temp\VMBuilds\CSense\mega_atmega2560\Debug/CSense.in
o.elf" [..removed rest of command ...]
ccNLxbjy.ltrans1.ltrans.o*: (.rodata+0x10a): undefined reference to vtable for __cxxabiv1::__class_type_info
ccNLxbjy.ltrans1.ltrans.o*: (.rodata+0x186): undefined reference to vtable for __cxxabiv1::__vmi_class_type_info
ccNLxbjy.ltrans1.ltrans.o*: (.rodata+0x19a): undefined reference to vtable for __cxxabiv1::__class_type_info
ccNLxbjy.ltrans1.ltrans.o*: (.rodata+0x19e): undefined reference to vtable for __cxxabiv1::__class_type_info
ccNLxbjy.ltrans1.ltrans.o*: (.rodata+0x1a2): undefined reference to vtable for __cxxabiv1::__si_class_type_info

How can I get rtti enabled ?

2

Are you sure that will work / fit on a microcontroller?

[ I can't easily find out if its implemented on avr-gcc for instance ]

3

No I'm not sure .. but al long as I don't get it to build, I won't know what the impact on binary size will be.

4

MarkT:
[ I can't easily find out if its implemented on avr-gcc for instance ]

It does compile... that would indicate to me that the compiler at least supports the dynamic_cast