getnetent_r(3) — Linux manual page


GETNETENT_R(3)            Linux Programmer's Manual           GETNETENT_R(3)

NAME         top

       getnetent_r,  getnetbyname_r,  getnetbyaddr_r  -  get  network  entry

SYNOPSIS         top

       #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:
           Glibc 2.19 and earlier:
               _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION         top

       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

       If the function call successfully obtains a network record, then
       *result is set pointing to result_buf; otherwise, *result is set to

       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         top

       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         top

       ENOENT (getnetent_r()) No more records in database.

       ERANGE buf is too small.  Try again with a larger buffer (and
              increased buflen).

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface         Attribute     Value          │
       │getnetent_r(),    │ Thread safety │ MT-Safe locale │
       │getnetbyname_r(), │               │                │
       │getnetbyaddr_r()  │               │                │

CONFORMING TO         top

       These functions are GNU extensions.  Functions with similar names
       exist on some other systems, though typically with different calling

SEE ALSO         top

       getnetent(3), networks(5)

COLOPHON         top

       This page is part of release 5.08 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

GNU                              2017-09-15                   GETNETENT_R(3)

Pages that refer to this page: endnetent(3)getnetbyaddr(3)getnetbyname(3)getnetent(3)setnetent(3)