Buñuel didn't throw me out, so I must have some talent, right?"

French screenwriter Jean-Claude Carrière has just turned 80. The man who wrote scripts with Luis Buñuel for 20 years and worked shoulder to shoulder with theater director Peter Brook over 35 seasons is in San Sebastián to promote a documentary about his life, 250 metros, directed by Juan Carlos Rulfo, and Monday's presentation coincided with his landmark birthday.

The occasion has given him time to laugh, do interviews, joke in his Frenchified Spanish, eat heartily and demonstrate his enormous humanity and love for his fellow man. "The world of tomorrow is going to be a mix, and I don't know if that is good or bad," he says. "Tomorrow will be for nomads, for pilgrim cultures. Nobody will have roots. And they will be even less deep, something that I consider dangerous, because it doesn't let you see the world." The 250 meters of the title is the distance from the house of his birth in Colombières-sur-Orb in southern France to his grave in the cemetery, where his first wife already awaits him. "I've had the luck to earn my living with my talent. And now I could live on very little, on 600 euros a month if I fail in the cinema or theater. I would eat what I grow in my vegetable patch," he says.

Asked about his two masters, Carrière says that "by luck" they were nothing like each other. "Luis was a block of granite, but with grains that don't end, with dark and beautiful nooks and crannies on the inside. Peter is not an author. He goes from one terrain to the next, spreading his fertility and his intelligence, a very sensitive intelligence. And he lets you work without you ever feeling tired. He is light, like an insect moving from one work to the other; Luis was a rock, robust."

In the end it didn't go badly for him: "Neither of the two threw me out, and they were and are the greatest. I must have some talent, right? I thought a lot about Luis today," he admits, "and it is a pleasure to recall my times with him... To have worked with a man like that leaves an important trace in your work and life. Even today, when I have to make a decision, I think about what Luis would have chosen in my place. He always answers me, even though he sometimes says, 'That's your problem'."

The film takes him to his Paris of the 1950s, to Toledo and Buñuel's Mexico, to the Madrid of "my master Luis" and of José Bergamín, to the hippy New York that he enjoyed with his close friend Milos Forman, and to the India of the Mahabharata, the epic that he spent 11 years adapting with Brook. And everywhere he laughs and happily says goodbye to those worlds to which he might not return. Or maybe he will: "These are my first 80 years," he says.