C Language, easy question, i hope..

easy question, i hope..

Author	Message
Aaron Masse #1 / 4	easy question, i hope.. Ok, I am trying to use the function and I'm #including math.h. There's a ton of online references that say this should work, but when I compile it I get this message: gcc -g -Wall zscore.c main.c -o main /tmp/ccevIzCM.o: In function `normalize': /home/masseya/zscore.c:242: undefined reference to `sqrt' collect2: ld returned 1 exit status Why doesn't this work? Is there an official reference that I should look at to see if sqrt() is in a different header file? Thanks for holding my hand for a newbie-ish question.. -Aaron
Fri, 04 Feb 2005 22:15:12 GMT

Jirka Klau #2 / 4	easy question, i hope.. Quote: > Ok, I am trying to use the function and I'm #including math.h. There's a > ton of online references that say this should work, but when I compile it > I get this message: > gcc -g -Wall zscore.c main.c -o main > /tmp/ccevIzCM.o: In function `normalize': > /home/masseya/zscore.c:242: undefined reference to `sqrt' > collect2: ld returned 1 exit status > Why doesn't this work? Is there an official reference that > I should look at [...] Yes, there is the FAQ. :-) http://www.eskimo.com/~scs/C-faq/q14.3.html Jirka
Fri, 04 Feb 2005 22:27:56 GMT

nrk #3 / 4	easy question, i hope.. Quote: > Ok, I am trying to use the function and I'm #including math.h. There's a > ton of online references that say this should work, but when I compile it > I get this message: > gcc -g -Wall zscore.c main.c -o main > /tmp/ccevIzCM.o: In function `normalize': > /home/masseya/zscore.c:242: undefined reference to `sqrt' > collect2: ld returned 1 exit status > Why doesn't this work? Is there an official reference that I should look > at to see if sqrt() is in a different header file? > Thanks for holding my hand for a newbie-ish question.. > -Aaron This isn't a C question, but a question specific to your compiler-linker setup. In your case, adding the magic word -lm to the end of that gcc line should solve the problem. The error message is from "ld" which is your linker and it is complaining that it can't find the definition of sqrt. -nrk.
Sat, 05 Feb 2005 02:27:54 GMT

u.. #4 / 4	easy question, i hope.. Quote: > Ok, I am trying to use the function and I'm #including math.h. There's a > ton of online references that say this should work, but when I compile it > I get this message: > gcc -g -Wall zscore.c main.c -o main > /tmp/ccevIzCM.o: In function `normalize': > /home/masseya/zscore.c:242: undefined reference to `sqrt' > collect2: ld returned 1 exit status > Why doesn't this work? Is there an official reference that I should look > at to see if sqrt() is in a different header file? Add a -lm to the compiler command line. That links in the math libraries. -- Joel
Sat, 05 Feb 2005 02:55:09 GMT

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