#include <arpa/inet.h>
The <arpa/inet.h> header shall define the in_addr structure as described in <netinet/in.h>.
The <arpa/inet.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.
uint32_t htonl(uint32_t); uint16_t htons(uint16_t); uint32_t ntohl(uint32_t); uint16_t ntohs(uint16_t);
The <arpa/inet.h> header shall define the uint32_t and uint16_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, socklen_t); 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> and <inttypes.h>.
The following sections are informative.
The System Interfaces volume of POSIX.1-2017, htonl(), inet_addr(), inet_ntop()
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 https://www.kernel.org/doc/man-pages/reporting_bugs.html .