cuserid(3s)cuserid(3s)Namecuserid - get character login name of the user
char ∗cuserid (s)
The subroutine generates a character-string representation of the login
name of the owner of the current process. If s is a NULL pointer, this
representation is generated in an internal static area, the address of
which is returned. Otherwise, s is assumed to point to an array of at
least characters; the representation is left in this array. The con‐
stant is defined in the <stdio.h> header file.
If the login name cannot be found, returns a NULL pointer; if s is not
a NULL pointer, a null character (\0) will be placed at s.
In POSIX mode, if s is not a NULL pointer, s is the return value.
When your program is compiled using the POSIX environment, returns the
name associated with the effective userid of the calling process. When
compiled in the BSD or System V environments, it returns the name asso‐
ciated with the login activity on the controlling terminal, if any.
Otherwise, it returns the same as in the POSIX environment.
See Alsogetlogin(3), getpwent(3)cuserid(3s)