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 *restrict result_buf,
                       char *restrict buf, size_t buflen,
                       struct netent **restrict result,
                       int *restrict h_errnop);
       int getnetbyname_r(const char *restrict name,
                       struct netent *restrict result_buf,
                       char *restrict buf, size_t buflen,
                       struct netent **restrict result,
                       int *restrict h_errnop);
       int getnetbyaddr_r(uint32_t net, int type,
                       struct netent *restrict result_buf,
                       char *restrict buf, size_t buflen,
                       struct netent **restrict result,
                       int *restrict h_errnop);

   Feature Test Macro Requirements for glibc (see

       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

       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         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 signatures.

SEE ALSO         top

       getnetent(3), networks(5)

COLOPHON         top

       This page is part of release 5.13 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                            2021-03-22                 GETNETENT_R(3)

Pages that refer to this page: getnetent(3)