getprotoent(3)
NAME
getprotoent, getprotobyname, getprotobynumber, setprotoent, endprotoent - get protocol entry
SYNOPSIS
#include <netdb.h> struct protoent *getprotoent(void); struct protoent *getprotobyname(const char *name); struct protoent *getprotobynumber(int proto); void setprotoent(int stayopen); void endprotoent(void);
DESCRIPTION
The getprotoent() function reads the next entry from the protocols database (see protocols(5)) and returns a protoent structure containing the broken-out fields from the entry. A connection is opened to the database if necessary. The getprotobyname() function returns a protoent structure for the entry from the database that matches the protocol name name. A connection is opened to the database if necessary. The getprotobynumber() function returns a protoent structure for the entry from the database that matches the protocol number number. A connection is opened to the database if necessary. The setprotoent() 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 getproto*() functions. The endprotoent() function closes the connection to the database. The protoent structure is defined in <netdb.h> as follows: struct protoent { char *p_name; /* official protocol name */ char **p_aliases; /* alias list */ int p_proto; /* protocol number */ } The members of the protoent structure are: p_name The official name of the protocol. p_aliases A NULL-terminated list of alternative names for the protocol. p_proto The protocol number.
RETURN VALUE
The getprotoent(), getprotobyname() and getprotobynumber() functions return a pointer to a statically allocated protoent structure, or a null pointer if an error occurs or the end of the file is reached.
FILES
/etc/protocols
protocol database file
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). ┌───────────────────┬───────────────┬──────────────────────────────┐ │Interface │ Attribute │ Value │ ├───────────────────┼───────────────┼──────────────────────────────┤ │getprotoent() │ Thread safety │ MT-Unsafe race:protoent │ │ │ │ race:protoentbuf locale │ ├───────────────────┼───────────────┼──────────────────────────────┤ │getprotobyname() │ Thread safety │ MT-Unsafe race:protobyname │ │ │ │ locale │ ├───────────────────┼───────────────┼──────────────────────────────┤ │getprotobynumber() │ Thread safety │ MT-Unsafe race:protobynumber │ │ │ │ locale │ ├───────────────────┼───────────────┼──────────────────────────────┤ │setprotoent(), │ Thread safety │ MT-Unsafe race:protoent │ │endprotoent() │ │ locale │ └───────────────────┴───────────────┴──────────────────────────────┘ In the above table, protoent in race:protoent signifies that if any of the functions setprotoent(), getprotoent(), or endprotoent() are used in parallel in different threads of a program, then data races could occur.
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, 4.3BSD.
SEE ALSO
getnetent(3), getprotoent_r(3), getservent(3), protocols(5)
COLOPHON
This page is part of release 4.09 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
