ultra sound distance undefined

We are trying to get the echo time display in the simple ide terminal - This is what we keep getting for an error.

We are very new to this... hope this is a simple fix!

Thanks to anyone willing to help!


Project Directory: C:/Users/ajansen3/Documents/SimpleIDE/My Projects/

SimpleIDE Version 1.0.2
C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/
C:/Users/ajansen3/Documents/SimpleIDE/ Updated on: 2016-12-16

propeller-elf-gcc.exe -v GCC 4.6.1 (propellergcc_v1_0_0_2408)
propeller-elf-gcc.exe -I . -L . -I C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/Utility/libsimpletools -L C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/Utility/libsimpletools/cmm/ -I C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/TextDevices/libsimpletext -L C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/TextDevices/libsimpletext/cmm/ -I C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/Protocol/libsimplei2c -L C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/Protocol/libsimplei2c/cmm/ -I C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/Sensor/libping -L C:/Users/ajansen3/Documents/SimpleIDE/Learn/Simple Libraries/Sensor/libping/cmm/ -o cmm/echo.elf -Os -mcmm -m32bit-doubles -fno-exceptions -std=c99 echo.c -lm -lsimpletools -lsimpletext -lsimplei2c -lping -lm -lsimpletools -lsimpletext -lsimplei2c -lm -lsimpletools -lsimpletext -lm -lsimpletools -lm
echo.c: In function 'main':
echo.c:8:5: error: 'distance' undeclared (first use in this function)
echo.c:8:5: note: each undeclared identifier is reported only once for each function it appears in
Done. Build Failed!