Open System Services Library Calls Reference Manual (G06.27+, H06.04+)

getservbyport(3) OSS Library Calls Reference Manual
NAME
getservbyport - Gets a network service entry by port number
LIBRARY
G-series native OSS processes: /G/system/sysnn/zinetsrl
H-series OSS processes: /G/system/zdllnnn/zinetdll
SYNOPSIS
#include <netdb.h>
struct servent *getservbyport (
int port,
const char *proto);
PARAMETERS
port Specifies the port number for the service, in network-byte order.
proto Specifies the protocol name to use when contacting the service.
DESCRIPTION
The getservbyport() function searches the /etc/services file sequentially until a match with the
port parameter and with the proto parameter is found. If the proto parameter is a null pointer,
any value in the /etc/services file will match.
The getservbyport() function returns a pointer to a structure of type servent whose members
specify data from the /etc/services network services database file. The netdb.h header file
defines the servent structure.
NOTES
The getservbyport() return value points to static data, which is overwritten by any subsequent
calls to getservbyport(), getservbyname( ), getservent(),orsetservent().
RETURN VALUES
Upon successful completion, the getservbyport() function returns a pointer to a servent struc-
ture if the matching entry was found, and a null pointer if no match was found. If the call to get-
servbyport() fails, a null pointer is returned.
ERRORS
getservbyport() does not set errno.
FILES
/etc/services The Internet network service name database file. Each record in the file occupies
a single line and has four fields: the official service name, the port number, the
protocol name, and aliases.
RELATED INFORMATION
Functions: getservbyname(3), getservent(3), setservent(3), endservent(3).
Files: services(4).
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