Can ETL be used with Atmel Studio?

0
votes

The Embedded Template Library provides the data structures of the STL without using dynamic allocation, to be used in embedded development.

I'm experimenting with the ATSAMD21 in Atmel Studio, and cannot use dynamic allocation. Therefore I tried the ETL, but it gives me the same errors I get when I'm trying to use STL:

Error       ld returned 1 exit status
Error       undefined reference to `_exit'
Error       undefined reference to `_close'
Error       undefined reference to `_fstat'
Error       undefined reference to `_isatty'
Error       undefined reference to `_lseek'
Error       undefined reference to `_read'
Error       undefined reference to `_sbrk'
Error       undefined reference to `_kill'
Error       undefined reference to `_getpid'
Error       undefined reference to `_write'

As far as I know, these errors mean that a wrong target architecture was selected for the compiler. However, that shouldn't be the case, because my program worked just fine before I defined a single ETL structure. Also, the ETL is composed of just a bunch of header files.

My guess was that ETL uses code from STL, and the gnu compiler included in Atmel Studio can't handle it. (but they why did they even include STL if it's completely unusable?)

However, ETL can supposedly be used even without STL.

So I defined #define ETL_NO_STL in my project, but I still get the same errors.

new

It seems to be working correctly in "release" mode, these errors only appear in "debug".

The differences between debug and release don't indicate me any use of STL in one, versus the other:

Debug:

"C:\Program Files (x86)\Atmel\Studio\7.0\toolchain\arm\arm-gnu-toolchain\bin\arm-none-eabi-g++.exe" -mthumb -D__SAMD21J18A__ -DDEBUG -I"C:\Program Files (x86)\Atmel\Studio\7.0\Packs\atmel\SAMD21_DFP\1.2.276\samd21a\include" -I"C:\Program Files (x86)\Atmel\Studio\7.0\Packs\arm\CMSIS\4.2.0\CMSIS\Include" -O1 -ffunction-sections -fno-rtti -fno-exceptions -mlong-calls -g3 -Wall -mcpu=cortex-m0plus -c -MD -MP -MF "main.d" -MT"main.d" -MT"main.o" -o "main.o" ".././main.cpp"

Release:

"C:\Program Files (x86)\Atmel\Studio\7.0\toolchain\arm\arm-gnu-toolchain\bin\arm-none-eabi-g++.exe" -mthumb -D__SAMD21J18A__ -DNDEBUG -I"C:\Program Files (x86)\Atmel\Studio\7.0\Packs\atmel\SAMD21_DFP\1.2.276\samd21a\include" -I"C:\Program Files (x86)\Atmel\Studio\7.0\Packs\arm\CMSIS\4.2.0\CMSIS\Include" -O1 -ffunction-sections -fno-rtti -fno-exceptions -mlong-calls -Wall -mcpu=cortex-m0plus -c -MD -MP -MF "main.d" -MT"main.d" -MT"main.o" -o "main.o" ".././main.cpp"

The only other difference is that the debug build has an extra line: Using "RunCompilerTask" task from assembly "C:\Program Files (x86)\Atmel\Studio\7.0\Extensions\Application\AvrGCC.dll".

The debugging level is not the cause. Setting it to g3, g2, g1, or turning it off doesn't change anything. The difference is whether NDEBUG is there in the command. Maybe without it there are some unnecessarily POSIX consistency checks performed?

2
c++stlarmembeddedatmelstudio
All those missing functions are POSIX system calls. Without knowing anything about ETL, have you configured it correctly? Perhaps it can't be used on systems not implementing some of the base POSIX functions? What does the documentation say? How does your configuration look like (reading the documentation you need to create a etl_profile.h file, please include it)? - Some programmer dude
@Someprogrammerdude : yes, I did create the profile header, and added ETL_TARGET_DEVICE_ARM to it. - vsz
Your Cortex M0 doesn't seem to have Linux. It appears to be a microcontroller, not a PC. Thus avoid the following things: dynamic allocation, C++, POSIX, STL, PC programming. - Lundin
Also, I would strongly recommend not compiling Atmel bloatware ASF below C++, because that will break the whole thing. It's pretty broken to begin with, even when compiled as C. Is it possible to use Atmel Studio without the bloatware libraries? - Lundin
@Lundin I'm not using ASF, and I'm not using dynamic allocation. And I'm not using POSIX, at least not knowingly. I've written C++ applications for this platform, they work fine. Now I need some trees which would be a hassle to implement manually. I've chosen ETL specifically because it's not using dynamic allocation, and ETL's multimap seemed perfect for the job. I used the arduino profile, which should support the simplest of microcontrollers, but I still get the above errors. - vsz

2 Answers

0
votes

The ETL is designed after the STL, that's true. But the STL is long gone as a library, obsolete as its contents were merged into the C++ Standard Library.

The symbols referenced are from the C Standard Library though, which is another library that's become part of the C++ Standard Library.

0
votes

A compromise solution can be to add the NDEBUG parameter in debug mode, while still specifying a debugging level (like -g2 or -g3)

This allows to use breakpoints and to watch the values of variables in a debugging session, the only downside seems to be that assert statements won't work, a feature much less often used in embedded development compared to other platforms.