ESP8266 Community Forum

This IDE has a serious issue with libm.a in that it will error with

c:/arduino/arduino-1.6.5/portable/packages/esp8266/tools/xtensa-lx106-elf-gcc/1.20.0-26-gb404fb9/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/lib\libm.a(lib_a-e_pow.o):(.literal+0x100): undefined reference to `__ieee754_sqrt'


I would like to find a libm.a that fixes the issue since only addition subtraction multiplication and division and modulo are available all other math functions are not working like powers etc.
I searched github but the libm.a I found has the issue so it may be a dependency between the 8266 IDE and 1.6.5
and 1.20.0-26-gb404fb9

Try the staging version which should have a fix for this problem.

https://github.com/esp8266/arduino#staging-version-

I've been running into this as well when trying to use the tcs33725 color sensor. Looking at the release dates of this post and the date of the stable release, is this fix in production? I'm asking. It appears that the link is adding release candidates for version 2.0? Are these the files you are referring to or was there something else there before? I know I had problems before with matching everything to the right version 1.6.5 so I didn't want to mess things up even more...

Wait...I might have my answer. I added the rc2 board and it compiled. And while "it" was just a sketch including the library for the sensor, that is more than what it was doing yesterday. So...can someone let this complete novice to this stuff know if installing 2.0 RC2 is the magic fix? I'm new but I'm persistent...this WILL work! With some help from all of you of course. Much thanks!

My joy was short lived...
I wrote the real sketch - and it compiled!

But..since I loaded the 2.0r2 board into the 1.6.5.IDE, I got the familiar error when trying to upload..
warning: espcomm_sync failed
error: espcomm_open failed

I'm in great need of help! Thanks!