What is the difference between read() and fread()?

Question

I'm reading source code of the linux tool badblocks. They use the read() function there. Is there a difference to the standard C fread() function? (I'm not counting the arguments as a difference.)

Answer 1

read() is a low level, unbuffered read. It makes a direct system call on UNIX.

fread() is part of the C library, and provides buffered reads. It is usually implemented by calling read() in order to fill its buffer.

Answer 2

Family read() -> open, close, read, write
Family fread() -> fopen, fclose, fread, fwrite

Family read:

• are system calls
• are not formatted IO: we have a non formatted byte stream

Family fread

• are functions of the standard C library (libc)
• use an internal buffer
• are formatted IO (with the "%.." parameter) for some of them
• use always the Linux buffer cache

More details here, although note that this post contains some incorrect information.