Why was the general in a carnival of joy?

The general was celebrating the fact that they'd held the enemy and ultimately won the battle.

"As another officer sped his horse after the first messenger, the general beamed upon the earth like a sun. In his eyes was a desire to chant a paean. He kept repeating, "They 've held 'em, by heavens!"

His excitement made his horse plunge, and he merrily kicked and swore at it. He held a little carnival of joy on horseback."