huschi.net

GETNETENT_R(3)             Linux Programmer's Manual            GETNETENT_R(3)
NAME
       getnetent_r,  getnetbyname_r, getnetbyaddr_r - get network entry (reen-
       trant)
SYNOPSIS
       #include <netdb.h>
       int getnetent_r(struct netent *result_buf, char *buf,
                       size_t buflen, struct netent **result,
                       int *h_errnop);
       int getnetbyname_r(const char *name,
                       struct netent *result_buf, char *buf,
                       size_t buflen, struct netent **result,
                       int *h_errnop);
       int getnetbyaddr_r(uint32_t net, int type,
                       struct netent *result_buf, char *buf,
                       size_t buflen, struct netent **result,
                       int *h_errnop);
   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
       getnetent_r(), getnetbyname_r(), getnetbyaddr_r():
           Since glibc 2.19:
               _DEFAULT_SOURCE
           Glibc 2.19 and earlier:
               _BSD_SOURCE || _SVID_SOURCE
DESCRIPTION
       The getnetent_r(), getnetbyname_r(), and getnetbyaddr_r() functions are
       the  reentrant  equivalents  of,  respectively, getnetent(3), getnetby-
       name(3), and getnetbynumber(3).  They differ in the way that the netent
       structure is returned, and in the function calling signature and return
       value.  This manual page describes just the differences from  the  non-
       reentrant functions.
       Instead  of returning a pointer to a statically allocated netent struc-
       ture as the function result, these functions copy  the  structure  into
       the location pointed to by result_buf.
       The  buf  array  is  used  to store the string fields pointed to by the
       returned netent structure.  (The nonreentrant functions allocate  these
       strings  in  static  storage.)   The size of this array is specified in
       buflen.  If buf is too small, the call fails with the error ERANGE, and
       the  caller  must  try again with a larger buffer.  (A buffer of length
       1024 bytes should be sufficient for most applications.)
       If the function  call  successfully  obtains  a  network  record,  then
       *result  is  set  pointing  to result_buf; otherwise, *result is set to
       NULL.
       The buffer pointed to by h_errnop is used  to  return  the  value  that
       would be stored in the global variable h_errno by the nonreentrant ver-
       sions of these functions.
RETURN VALUE
       On success, these functions return 0.  On error, they return one of the
       positive error numbers listed in ERRORS.
       On error, record not found (getnetbyname_r(), getnetbyaddr_r()), or end
       of input (getnetent_r()) result is set to NULL.
ERRORS
       ENOENT (getnetent_r()) No more records in database.
       ERANGE buf is too small.  Try again with a larger buffer (and increased
              buflen).
ATTRIBUTES
       For   an   explanation   of   the  terms  used  in  this  section,  see
       attributes(7).
       +------------------+---------------+----------------+
       |Interface         | Attribute     | Value          |
       +------------------+---------------+----------------+
       |getnetent_r(),    | Thread safety | MT-Safe locale |
       |getnetbyname_r(), |               |                |
       |getnetbyaddr_r()  |               |                |
       +------------------+---------------+----------------+
CONFORMING TO
       These functions are GNU extensions.  Functions with similar names exist
       on  some  other systems, though typically with different calling signa-
       tures.
SEE ALSO
       getnetent(3), networks(5)
COLOPHON
       This page is part of release 4.15 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                    GETNETENT_R(3)