getusershell, setusershell, endusershell - get legal user shells

#include <unistd.h>
 char *getusershell(void);
 void setusershell(void);
 void endusershell(void);

The R getusershell () function returns the next line from the file /etc/shells, opening the file if necessary. The line should contain the pathname of a valid user shell. If /etc/shells does not exist or is unreadable, R getusershell () behaves as if /bin/sh and /bin/csh were listed in the file.

The R setusershell () function rewinds /etc/shells.

The R endusershell () function closes /etc/shells.

The R getusershell () function returns a NULL pointer on end-of-file.

/etc/shells

4.3BSD

shells(5)