Subject: link time errors

(This message is being sent to CPSC 215 Students and TA's)


/var/tmp//ccfz83ip.o(.text+0x70): In function `vl_length3':
: undefined reference to `sqrt'
collect2: ld returned 1 exit status


If your program contains references to math functions such
sqrt() even if you don't actually call the function you
must use the following to the command line:

gcc -Wall -g main.c projection.c veclib.c -lm

The character preceding the  "m" in the -lm flag
is a lower case L and NOT the numeral 1.

The -lm instructs the linker to use the mathematical
function library.