endaliasent

SETALIASENT(3)		 access mail aliases database	       SETALIASENT(3)



NAME
       setaliasent,  endaliasent, getaliasent, getaliasent_r, getaliasbyname,
       getaliasbyname_r - read an alias entry

SYNOPSIS
       #include <aliases.h>

       void setaliasent(void);

       void endaliasent(void);

       struct aliasent *getaliasent(void);

       int getaliasent_r(struct aliasent *result,
	   char *buffer, size_t buflen, struct aliasent **res);

       struct aliasent *getaliasbyname(const char *name);

       int getaliasbyname_r(const char *name,
	   struct aliasent *result,
	   char *buffer, size_t buflen, struct aliasent **res);


DESCRIPTION
       One of the databases available with the Name Service Switch  (NSS)  is
       the  aliases  database, that contains mail aliases. (To find out which
       databases are supported, try  getent --help .)  Six functions are pro-
       vided to access the aliases database.

       The getaliasent() function returns a pointer to a structure containing
       the group information from the aliases database.	 The first time it is
       called  it  returns the first entry; thereafter, it returns successive
       entries.

       The setaliasent() function rewinds the file pointer to  the  beginning
       of the aliases database.

       The endaliasent() function closes the aliases database.

       getaliasent_r() is the reentrant version of the previous function. The
       requested structure is stored via the first argument but the  program-
       mer needs to fill the other arguments also. Not providing enough space
       causes the function to fail.

       The function getaliasbyname() takes the name argument and searches the
       aliases	database.  The	entry  is  returned  as a pointer to a struct
       aliasent.

       getaliasbyname_r() is the reentrant version of the previous  function.
       The requested structure is stored via the second argument but the pro-
       grammer need to fill the other arguments also.  Not  providing  enough
       space causes the function to fail.

       The struct aliasent is defined in <aliases.h>.
       struct aliasent {
	   char *alias_name;		  /* alias name */
	   size_t alias_members_len;
	   char **alias_members;	  /* alias name list */
	   int alias_local;
       };

FILES
       The  default  alias  database  is  the file /etc/aliases.  This can be
       changed in the /etc/nsswitch.conf file.

RETURN VALUE
       The functions getaliasent_r() and getaliasbyname_r() return a non-zero
       value on error.

EXAMPLE
       The  following  example	compiles  with gcc example.c -o example .  It
       will dump all names in the alias database.

       #include <aliases.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <errno.h>

       int main() {
	 struct aliasent *al;
	 setaliasent();
	 for (;;) {
	   al = getaliasent();
	   if (al == NULL) break;
	   printf("Name: %s\n", al->alias_name);
	 }
	 if (errno) {
	     perror("reading alias");
	     exit(EXIT_FAILURE);
	 }
	 endaliasent();
	 exit(EXIT_SUCCESS);
       }

CONFORMING TO
       These routines are glibc-specific.  The NeXT has similar routines
	      #include <aliasdb.h>
	      void alias_setent(void);
	      void alias_endent(void);
	      alias_ent *alias_getent(void);
	      alias_ent *alias_getbyname(char *name);

SEE ALSO
       getgrent(3), getpwent(3), getspent(3), aliases(5)



GNU				  2003-09-09		       SETALIASENT(3)