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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | VERSIONS | STANDARDS | SEE ALSO | COLOPHON |
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getnetent_r(3) Library Functions Manual getnetent_r(3)
getnetent_r, getnetbyname_r, getnetbyaddr_r - get network entry
(reentrant)
Standard C library (libc, -lc)
#include <netdb.h>
int getnetent_r(size_t size;
struct netent *restrict result_buf,
char buf[restrict size], size_t size,
struct netent **restrict result,
int *restrict h_errnop);
int getnetbyname_r(size_t size;
const char *restrict name,
struct netent *restrict result_buf,
char buf[restrict size], size_t size,
struct netent **restrict result,
int *restrict h_errnop);
int getnetbyaddr_r(size_t size;
uint32_t net, int type,
struct netent *restrict result_buf,
char buf[restrict size], size_t size,
struct netent **restrict result,
int *restrict 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 size. 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 size 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.
ENOENT (getnetent_r()) No more records in database.
ERANGE buf is too small. Try again with a larger buffer (and
increased size).
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() │ │ │
└───────────────────────────────┴───────────────┴────────────────┘
Functions with similar names exist on some other systems, though
typically with different calling signatures.
GNU.
getnetent(3), networks(5)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-06-28 getnetent_r(3)
Pages that refer to this page: getnetent(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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