ESP32 Forum

Posted: **Thu Sep 29, 2016 5:16 am**

I have some code that is including "math.h" from components/newlib/include/math.h

In that header there is an external reference to:

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extern int __fpclassifyd (double x);

when I link my application, I am getting an error stating:

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jswrap_functions.c:(.text.jswrap_parseInt+0x27): undefined reference to `__fpclassifyd'

It is important to note that the link step I am using is the following:

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xtensa-esp32-elf-gcc -Winline -Og -Wl,--gc-sections -nostdlib -u call_user_start_cpu0 \
-Wl,--gc-sections -Wl,-static -Wl,-EL \
-Wl,--start-group \
-T/home/pi/projects/esp32/esp-idf/components/esp32/ld/esp32.ld \
-T/home/pi/projects/esp32/esp-idf/components/esp32/ld/esp32.common.ld \
-T/home/pi/projects/esp32/esp-idf/components/esp32/ld/esp32.rom.ld \
-T/home/pi/projects/esp32/esp-idf/components/esp32/ld/esp32.peripherals.ld \
/home/pi/projects/esp32/esp-idf/components/newlib/lib/libc.a \
/home/pi/projects/esp32/esp-idf/components/newlib/lib/libm.a \
-Wl,--end-group -o espruino_1v87.213_esp32.elf src/jslex.o .... // many more .o files

I also found a mysterious file called "components/newlib/lib/extracted/romsys" which appears to list the entry "__fpclassifyd".

Can anyone spot where I must possibly be going wrong?

Posted: **Thu Sep 29, 2016 6:29 am**

It is listed in romsys but not in esp32.rom.ld so can't be linked

Posted: **Thu Sep 29, 2016 7:27 am**

Can you file an issue on Github for this? Sounds like the script that generates the rom ld file may have skipped over this because of the double underscore.

Posted: **Thu Sep 29, 2016 1:47 pm**

Thank you guys. Git hub issue #33 raised.

Later ...

The problem was resolved and it was discovered to be a mistake on my part in my linking step. I had failed to include my source compiled object files in the --start-group / --end-group recursive linking definition. Once I moved my code to be within the recursive resolution group, the linker completed without error.

To be explicit ... I was linking incorrectly with:

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-Wl,--start-group <ESP-IDF libs> -Wl,--end-group <my object files>

when what I should have been doing was:

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-Wl,--start-group <ESP-IDF libs> <my object files> -Wl,--end-group

If you are using the ESP-IDF makefiles, you shouldn't ever have to worry about this knowledge. I include for completeness in case a similar error is encountered down the line and these words may provide hints to the next person.

Posted: **Fri Sep 30, 2016 2:17 am**

So how does this reconcile the mismatch between romsys and esp32.rom.ld?

ESP32 Forum

[Solved] Problems linking with math library - undefined "__fpclassifyd"

[Solved] Problems linking with math library - undefined "__fpclassifyd"

Re: Problems linking with math library - undefined "__fpclassifyd"

Re: Problems linking with math library - undefined "__fpclassifyd"

Re: Problems linking with math library - undefined "__fpclassifyd"

Re: Problems linking with math library - undefined "__fpclassifyd"