On Thu, Sep 04, 2003 at 05:53:54AM +0200, didier wrote: > I have installed gcc 3.3.1 on a PC-linux system, with bootstrap by gcc > 2.96. Every thing was right. But in a test program, the calll of the > "exp" function generated an error message " undefined reference to > 'exp', thought I include the file <math.h>. What is the reason ? Including a header file usually is not enough as it usually only contains function declarations / prototypes. You need to link with the math library `libm' which provides the compiled code for the various math functions such as `exp': gcc prog.c -lm -- Claudio Bley ASCII ribbon campaign (") Debian GNU/Linux user - against HTML email X http://www.cs.uni-magdeburg.de/~bley/ & vCards / \