The endoergic reactions of C+(P-2(u)) with CO((1)Sigma(+)) producing CO++C, C-2(+)+O, and O++C-2 have been studied in a guided-ion beam apparatus. For each reaction channel, we have measured the kinetic energy dependence of the integral cross section and the reaction threshold. Analysis of the reaction cross sections yield the heats of formation Delta(f)H(0)(C-2(+))=19.79 +/- 0.16 and Delta(f)H(0)(C-2)=8.37 +/- 0.16 eV. In addition the dissociation energy of C-2 is estimated to be D-0(C-C)=6.37 +/- 0.16 eV. A simple state correlation diagram is used to rationalize experimental observations and to discuss reaction dynamics.