从管道读取的字节数

When reading from a pipe in Linux (C, fread/similar), when EOF is reached, how can it be known how many bytes were read? If I read blocks at a time, fread() only returns the number of full blocks read in, and I can't read one byte at a time because that is too slow. Of course, ftell() returns -1.When reading from a pipe in Linux (C, fread/sim