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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | FILES | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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getservent(3) Library Functions Manual getservent(3)
getservent, getservbyname, getservbyport, setservent, endservent
- get service entry
Standard C library (libc, -lc)
#include <netdb.h>
struct servent *getservent(void);
struct servent *getservbyname(const char *name, const char *proto);
struct servent *getservbyport(int port, const char *proto);
void setservent(int stayopen);
void endservent(void);
The getservent() function reads the next entry from the services
database (see services(5)) and returns a servent structure
containing the broken-out fields from the entry. A connection is
opened to the database if necessary.
The getservbyname() function returns a servent structure for the
entry from the database that matches the service name using
protocol proto. If proto is NULL, any protocol will be matched.
A connection is opened to the database if necessary.
The getservbyport() function returns a servent structure for the
entry from the database that matches the port port (given in
network byte order) using protocol proto. If proto is NULL, any
protocol will be matched. A connection is opened to the database
if necessary.
The setservent() function opens a connection to the database, and
sets the next entry to the first entry. If stayopen is nonzero,
then the connection to the database will not be closed between
calls to one of the getserv*() functions.
The endservent() function closes the connection to the database.
The servent structure is defined in <netdb.h> as follows:
struct servent {
char *s_name; /* official service name */
char **s_aliases; /* alias list */
int s_port; /* port number */
char *s_proto; /* protocol to use */
}
The members of the servent structure are:
s_name The official name of the service.
s_aliases
A NULL-terminated list of alternative names for the
service.
s_port The port number for the service given in network byte
order.
s_proto
The name of the protocol to use with this service.
The getservent(), getservbyname(), and getservbyport() functions
return a pointer to a statically allocated servent structure, or
NULL if an error occurs or the end of the file is reached.
/etc/services
services database file
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────┬───────────────┬─────────────────────────────┐
│ Interface │ Attribute │ Value │
├─────────────────┼───────────────┼─────────────────────────────┤
│ getservent() │ Thread safety │ MT-Unsafe race:servent │
│ │ │ race:serventbuf locale │
├─────────────────┼───────────────┼─────────────────────────────┤
│ getservbyname() │ Thread safety │ MT-Unsafe race:servbyname │
│ │ │ locale │
├─────────────────┼───────────────┼─────────────────────────────┤
│ getservbyport() │ Thread safety │ MT-Unsafe race:servbyport │
│ │ │ locale │
├─────────────────┼───────────────┼─────────────────────────────┤
│ setservent(), │ Thread safety │ MT-Unsafe race:servent │
│ endservent() │ │ locale │
└─────────────────┴───────────────┴─────────────────────────────┘
In the above table, servent in race:servent signifies that if any
of the functions setservent(), getservent(), or endservent() are
used in parallel in different threads of a program, then data
races could occur.
POSIX.1-2008.
POSIX.1-2001, 4.3BSD.
getnetent(3), getprotoent(3), getservent_r(3), services(5)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
Linux man-pages 6.9.1 2024-05-02 getservent(3)
Pages that refer to this page: getent(1), byteorder(3), getaddrinfo(3), getnameinfo(3), getnetent(3), getprotoent(3), getservent_r(3), rexec(3), setnetgrent(3), nss(5), nsswitch.conf(5), services(5)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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