What memory do libc system calls run in?

Question

linux

I deal with User Space and Kernel Space, I found out that the processes of the kernel itself are launched in the Kernel space, aka the code that was loaded from under the Kernel. Userspace is the memory where standard user processes run.
The question is, do processes called from Libc (glibc) run in Kernel or User space, or both? (as I know, we constantly refer to libc during a system call)
Please correct me if I'm floating ....
Thank you.

Answer 1

processes called from Libc (glibc) run in Kernel or User space

libc is part of the user process. It accesses the kernel through system calls. System calls are made by the kernel in kernel space. libc does additional processing in user space, such as converting error codes and updating errno.
For example, the program calls printf (3) , libc parses the format string in a loop and calls the write (2) system call , execution switches to kernel mode, the kernel prints characters to the stdout of the current process, execution returns to user space, libc checks that there were no errors and either continues the loop to the end of the format string, or updates errno and returns the result.
Some libc functions run entirely in userspace, such as sprintf (3) .