putpwent is the inverse of
getpwent(S).
Given a pointer to a passwd
structure created by getpwent
(or getpwuid
or getpwnam),
putpwent
writes a line on the stream
f,
which matches the format of
/etc/passwd.
Return values
putpwent returns non-zero
if an error was detected during its operation;
otherwise, it returns zero.
p, FILE