What is the difference between system call and library call?

Can someone explain the differences for these two in linux? Please go as deep as possible into each step the operating system takes.

Solution

Low level kernel calls which are handled by the kernel are the system calls.

The man page says:

2 System calls (functions provided by the kernel)

3 Library calls (functions within program libraries)

A pictorial image can make it clear:

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and

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