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.
- ENOENT
- (getnetent_r()) No more records in database.
- ERANGE
- 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.
getnetent(3),
networks(5)