getnetent_r, getnetbyname_r, getnetbyaddr_r - get network entry (reentrant)
#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
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.
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.
(getnetent_r()) No more records in database.
buf
is too small. Try again with a larger buffer (and
increased buflen
).
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
getnetent_r(), getnetbyname_r(), getnetbyaddr_r() | Thread safety | MT-Safe locale |
These functions are GNU extensions. Functions with similar names exist on some other systems, though typically with different calling signatures.
This page is part of release 5.10 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/.