rpmatch  -  determine  if  the  answer  to a question is affirmative or


   #include <stdlib.h>

   int rpmatch(const char *response);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       Since glibc 2.19:
       Glibc 2.19 and earlier:


   rpmatch() handles a user response to yes or no questions, with  support
   for internationalization.

   response  should be a null-terminated string containing a user-supplied
   response, perhaps obtained with fgets(3) or getline(3).

   The  user's  language  preference  is  taken  into  account   per   the
   environment variables LANG, LC_MESSAGES, and LC_ALL, if the program has
   called setlocale(3) to effect their changes.

   Regardless of the locale, responses matching ^[Yy] are always  accepted
   as  affirmative,  and  those  matching  ^[Nn]  are  always  accepted as


   After examining response, rpmatch() returns 0 for a recognized negative
   response  ("no"),  1 for a recognized positive response ("yes"), and -1
   when the value of response is unrecognized.


   A return value of -1 may indicate either  an  invalid  input,  or  some
   other  error.   It  is  incorrect  to  only test if the return value is

   rpmatch() can fail for any of the reasons that regcomp(3) or regexec(3)
   can  fail;  the  cause  of  the  error  is  not available from errno or
   anywhere else, but indicates a failure of the regex  engine  (but  this
   case  is  indistinguishable  from  that  of  an  unrecognized  value of


   For  an  explanation  of  the  terms  used   in   this   section,   see

   Interface  Attribute      Value          
   rpmatch()  Thread safety  MT-Safe locale 


   rpmatch()  is  not  required by any standard, but is available on a few
   other systems.


   The rpmatch() implementation looks  at  only  the  first  character  of
   response.   As  a  consequence, "nyes" returns 0, and "ynever; not in a
   million years" returns 1.  It  would  be  preferable  to  accept  input
   strings  much  more  strictly,  for example (using the extended regular
   expression  notation  described  in  regex(7)):  ^([yY]|yes|YES)$   and


   The following program displays the results when rpmatch() is applied to
   the string given in the program's command-line argument.

   #define _SVID_SOURCE
   #include <locale.h>
   #include <stdlib.h>
   #include <string.h>
   #include <stdio.h>

   main(int argc, char *argv[])
       if (argc != 2 || strcmp(argv[1], "--help") == 0) {
           fprintf(stderr, "%s response\n", argv[0]);

       setlocale(LC_ALL, "");
       printf("rpmatch() returns: %d\n", rpmatch(argv[1]));


   fgets(3), getline(3), nl_langinfo(3), regcomp(3), setlocale(3)


   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


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.


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.