“从儿童过程15 ***分叉后”的含义？

when I use linux console to develop, I use gdb to trace the program's behavior, Always the console print "Detaching after fork from child process 15***." can any body help to explain the sentence in quotation mark? How and Who will do What jobs after Detaching from child process? Thanks first:)when I use linux console to develop, I use gdb