ENDSERVENT(P) ENDSERVENT(P)
NAME
endservent, getservbyname, getservbyport, getservent, setservent - network services
database functions
SYNOPSIS
#include <netdb.h>
void endservent(void);
struct servent *getservbyname(const char *name, const char *proto);
struct servent *getservbyport(int port, const char *proto);
struct servent *getservent(void);
void setservent(int stayopen);
DESCRIPTION
These functions shall retrieve information about network services. This information is
considered to be stored in a database that can be accessed sequentially or randomly. The
implementation of this database is unspecified.
The setservent() function shall open a connection to the database, and set the next entry
to the first entry. If the stayopen argument is non-zero, the net database shall not be
closed after each call to the getservent() function (either directly, or indirectly
through one of the other getserv*() functions), and the implementation may maintain an
open file descriptor for the database.
The getservent() function shall read the next entry of the database, opening and closing a
connection to the database as necessary.
The getservbyname() function shall search the database from the beginning and find the
first entry for which the service name specified by name matches the s_name member and the
protocol name specified by proto matches the s_proto member, opening and closing a connec-
tion to the database as necessary. If proto is a null pointer, any value of the s_proto
member shall be matched.
The getservbyport() function shall search the database from the beginning and find the
first entry for which the port specified by port matches the s_port member and the proto-
col name specified by proto matches the s_proto member, opening and closing a connection
to the database as necessary. If proto is a null pointer, any value of the s_proto member
shall be matched. The port argument shall be in network byte order.
The getservbyname(), getservbyport(), and getservent() functions shall each return a
pointer to a servent structure, the members of which shall contain the fields of an entry
in the network services database.
The endservent() function shall close the database, releasing any open file descriptor.
These functions need not be reentrant. A function that is not required to be reentrant is
not required to be thread-safe.
RETURN VALUE
Upon successful completion, getservbyname(), getservbyport(), and getservent() return a
pointer to a servent structure if the requested entry was found, and a null pointer if the
end of the database was reached or the requested entry was not found. Otherwise, a null
pointer is returned.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
The port argument of getservbyport() need not be compatible with the port values of all
address families.
The getservbyname(), getservbyport(), and getservent() functions may return pointers to
static data, which may be overwritten by subsequent calls to any of these functions.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
endhostent() , endprotoent() , htonl() , inet_addr() , the Base Definitions volume of
IEEE Std 1003.1-2001, <netdb.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
POSIX 2003 ENDSERVENT(P)
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