Hi, The "sqrt" function is in libm, you should use: gcc PROGRAM_NAME -lm Venkatesh > > Hi, all > > I had a function and cc it in redhat 7.2, > but if I use > $gcc PROGRAM_NAME, > there will be error : > > /tmp/ccAXzZTF.o: In function `main': > /tmp/ccAXzZTF.o(.text+0x32): undefined reference to `sqrt' > collect2: ld returned 1 exit status > > but if I use -O or -O2 to gcc, it works well !! > I do not know why, the following is source code > > > #include <stdio.h> > #include <math.h> > > int main(void) > { > > double pi = M_PI; > double pisqrt; > long i; > > for (i = 0; i < 10000000; ++i) { > pisqrt = sqrt(pi); > } > return 0; > } > > > > _______________________________________________ > Redhat-devel-list mailing list > Redhat-devel-list@redhat.com > https://listman.redhat.com/mailman/listinfo/redhat-devel-list > _______________________________________________ Redhat-devel-list mailing list Redhat-devel-list@redhat.com https://listman.redhat.com/mailman/listinfo/redhat-devel-list