This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding Linux
manual page for details of Linux behavior), or the interface may not be
implemented on Linux.
arpa/inet.h — definitions for internet operations
header shall define the in_port_t
types as described in <netinet/in.h>
header shall define the in_addr
as described in <netinet/in.h>
header shall define the INET_ADDRSTRLEN and
INET6_ADDRSTRLEN macros as described in <netinet/in.h>
The following shall be declared as functions, or defined as macros, or both. If
functions are declared, function prototypes shall be provided.
header shall define the uint32_t
types as described in <inttypes.h>
The following shall be declared as functions and may also be defined as macros.
Function prototypes shall be provided.
in_addr_t inet_addr(const char *);
char *inet_ntoa(struct in_addr);
const char *inet_ntop(int, const void *restrict, char *restrict,
int inet_pton(int, const char *restrict, void *restrict);
Inclusion of the <arpa/inet.h>
header may also make visible all
symbols from <netinet/in.h>
The following sections are informative.
The System Interfaces volume of POSIX.1‐2008, htonl()
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2013 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
7, Copyright (C) 2013 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013
Technical Corrigendum 1 applied.) In the event of any discrepancy between this
version and the original IEEE and The Open Group Standard, the original IEEE
and The Open Group Standard is the referee document. The original Standard can
be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are most likely
to have been introduced during the conversion of the source files to man page
format. To report such errors, see