puts / putchar¶ 可以简单测试一下 1 2 3cd test make nbuf.out strace ./nbuf.out 1 2 3 4write(1, "xyz", 3xyz) = 3 write(1, "x", 1x) = 1 write(1, "y", 1y) = 1 write(1, "z", 1z) = 1