about the link error with arm-none-eabi on the eclipse environment.

RE: about the link error with arm-none-eabi on the eclipse environment.

Raphael — Wed, 06 Jan 2016 14:37:53 GMT

Worked just fine with LD as a linker command for me (ARM GCC 4.9.3). See my answer.

RE: about the link error with arm-none-eabi on the eclipse environment.

Raphael — Wed, 06 Jan 2016 14:36:35 GMT

You need to tell the linker to actually link in the math library (libm). The header include only includes the declaration, but then of course at link time the code won't be included if you don't tell the linker. Different than the C standard library, math.h constitutes an additional library which the linker won't include by default.

If you are using a makefile that is based on Nordic's GCC / GNU make makefile, simply add

LIBS = -lm

LIBS += -lm

in your makefile.

The example makefile from Nordic does include $(LIBS) in the targets, but LIBS is never defined. You of course need to use the second variant if you defined LIBS yourself.

RE: about the link error with arm-none-eabi on the eclipse environment.

maxpaynner — Wed, 22 Apr 2015 10:42:46 GMT

This works

RE: about the link error with arm-none-eabi on the eclipse environment.

maxpaynner — Sat, 18 Apr 2015 16:33:28 GMT

I had this same problem.

The solution was:

1- Link with GCC instead of LD (some guys recommend this, dunno where I read it, but seems to work). In your makefile replace

LD       		:= "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-ld"

With

LD       		:= "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-gcc"

2- Manually add the math lib to your libs

#link math library.. dunno why this isn't done automatically

LIBS += $(GNU_INSTALL_ROOT)/arm-none-eabi/lib/thumb/libm.a

I don't know why the linker doesn't automatically link the library but this seemed to work for me.

RE: about the link error with arm-none-eabi on the eclipse environment.

Ole Morten — Mon, 16 Dec 2013 16:39:08 GMT

You're right, I see the same when I tried this modification. To make it work, I had to add -lm to the linking command line. Beware that the place in the line actually matters, but things seemed to work when I put it right before the -o parameter in the final linking: $(CC) $(LDFLAGS) $(C_OBJECTS) $(ASSEMBLER_OBJECTS) $(LIBRARIES) -lm -o $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out

RE: about the link error with arm-none-eabi on the eclipse environment.

Markus Roppelt — Tue, 10 Dec 2013 18:08:26 GMT

I can compile the attached math-lib.zip. However if I change the the argument to a variable I get following error.

main.c:(.text.startup+0x5a): undefined reference to `atan2'
collect2.exe: error: ld returned 1 exit status
make: *** [_build/template_project_gcc_s110_xxaa.out] Fehler 1

My main is:


int main(void)
{	
	uint8_t idx = 0;
	double d_idx = 0.0;
	uint8_t buffer[20];
	simple_uart_config(0, 17, 0, 16, false);
	simple_uart_putstring((uint8_t *)"Start\r\n");
	nrf_gpio_range_cfg_output(8, 15);
	
	while (true)
    {
		idx++;
		d_idx = (double) idx;
		float result = atan2(1.0, d_idx);
		sprintf((char *)buffer, "%f\r\n", result);
		simple_uart_putstring(buffer);
		nrf_delay_us(100000);
    }
}

How can I build this?

Greetings Markus

RE: about the link error with arm-none-eabi on the eclipse environment.

Ole Morten — Fri, 13 Sep 2013 11:53:23 GMT

As far as I can see, this just works out of the box. Please see the attached example, that should compile directly if you put it in the Board/nrf6310/ folder, both with SDK version 4.3.0 and 4.4.0. If you still struggle, could you please upload your complete project, including any Makefiles and linker scripts?

math-lib.zip