NAME

       getnetent_r, getnetbyname_r, getnetbyaddr_r - get network entry (reentrant)

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), getnetbyname(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
       nonreentrant functions.

       Instead  of returning a pointer to a statically allocated netent structure 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 versions 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 signatures.

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/.