What is the difference between open and create function in c?

Question

Can someone help me with the example when to use normal function calling and when pointer function calling. What was the reason for introducing pointer function calling in C?

Answer 1

The creat function creates files, but can not open existing file. If using creat on an existing file, the file will be truncated and can only be written to.

open is a system call that is used to open a new file and obtain its file descriptor.This system call can also be used for creating a file before opening it.

Comments

which system call is used just to create a file not open ?

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internal implementation of creat.
int creat(const char *path, mode_t mode)
{
    return open(path, O_WRONLY|O_CREAT|O_TRUNC, mode);
}