GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


man:endaliasent

SETALIASENT(3) Linux Programmer's Manual 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 programmer
     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 needs 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; };

RETURN VALUE

     The  functions  getaliasent_r() and getaliasbyname_r() return a nonzero
     value on error.

FILES

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

ATTRIBUTES

     For   an   explanation   of   the  terms  used  in  this  section,  see
     attributes(7).
     allbox; lbw19 lb lb l l l.  Interface Attribute Value T{ setaliasent(),
     endaliasent(), getaliasent_r(), getaliasbyname_r() T}   Thread
     safety  MT-Safe locale T{ getaliasent(), getaliasbyname() T}   Thread
     safety  MT-Unsafe

CONFORMING TO

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

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(void) {
         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); }

SEE ALSO

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

COLOPHON

     This  page  is  part of release 4.16 of the Linux man-pages project.  A
     description of the project, information about reporting bugs,  and  the
     latest     version     of     this    page,    can    be    found    at
     https://www.kernel.org/doc/man-pages/.

GNU 2017-09-15 SETALIASENT(3)

/data/webs/external/dokuwiki/data/pages/man/endaliasent.txt · Last modified: 2019/05/17 09:32 by 127.0.0.1

Was this page helpful?-10+1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki