LinuxGuruz
  • Last 5 Forum Topics
    Replies
    Views
    Last post


The Web Only This Site
  • BOOKMARK

  • ADD TO FAVORITES

  • REFERENCES


  • MARC

    Mailing list ARChives
    - Search by -
     Subjects
     Authors
     Bodies





    FOLDOC

    Computing Dictionary




  • Text Link Ads






  • LINUX man pages
  • Linux Man Page Viewer


    The following form allows you to view linux man pages.

    Command:

    getservent_r

    
    
    
    

    SYNOPSIS

           #include <netdb.h>
    
           int getservent_r(struct servent *result_buf, char *buf,
                           size_t buflen, struct servent **result);
    
           int getservbyname_r(const char *name, const char *proto,
                           struct servent *result_buf, char *buf,
                           size_t buflen, struct servent **result);
    
           int getservbyport_r(int port, const char *proto,
                           struct servent *result_buf, char *buf,
                           size_t buflen, struct servent **result);
    
       Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
    
           getservent_r(), getservbyname_r(), getservbyport_r():
               _BSD_SOURCE || _SVID_SOURCE
    
    
    

    DESCRIPTION

           The getservent_r(), getservbyname_r(), and getservbyport_r()  functions
           are  the  reentrant  equivalents  of, respectively, getservent(3), get-
           servbyname(3), and getservbyport(3).  They differ in the way  that  the
           servent  structure  is  returned, and in the function calling signature
           and return value.  This manual page describes just the differences from
           the nonreentrant functions.
    
           Instead of returning a pointer to a statically allocated servent struc-
           ture as the function result, these functions copy  the  structure  into
           the location pointed to by result_buf.
    
           The  buf  array  is  used  to store the string fields pointed to by the
           returned servent structure.  (The nonreentrant functions allocate these
           strings  in  static  storage.)   The size of this array is specified in
           buflen.  If buf is too small, the call fails with the error ERANGE, and
           the  caller  must  try again with a larger buffer.  (A buffer of length
           1024 bytes should be sufficient for most applications.)
    
           If the function  call  successfully  obtains  a  service  record,  then
           *result  is  set  pointing  to result_buf; otherwise, *result is set to
           NULL.
    
    
    

    RETURN VALUE

           On success, these functions return 0.  On error, they return one of the
           positive error numbers listed in errors.
    
           On  error,  record not found (getservbyname_r(), getservbyport_r()), or
           end of input (getservent_r()) result is set to NULL.
    
    
    

    ERRORS

           ENOENT (getservent_r()) No more records in database.
           ERANGE,  the  program  retries with larger buffer sizes.  The following
           shell session shows a couple of sample runs:
    
               $ ./a.out 7 tcp 1
               ERANGE! Retrying with larger buffer
               getservbyport_r() returned: 0 (success)  (buflen=87)
               s_name=echo; s_proto=tcp; s_port=7; aliases=
               $ ./a.out 77777 tcp
               getservbyport_r() returned: 0 (success)  (buflen=1024)
               Call failed/record not found
    
       Program source
    
           #define _GNU_SOURCE
           #include <ctype.h>
           #include <netdb.h>
           #include <stdlib.h>
           #include <stdio.h>
           #include <errno.h>
           #include <string.h>
    
           #define MAX_BUF 10000
    
           int
           main(int argc, char *argv[])
           {
               int buflen, erange_cnt, port, s;
               struct servent result_buf;
               struct servent *result;
               char buf[MAX_BUF];
               char *protop;
               char **p;
    
               if (argc < 3) {
                   printf("Usage: %s port-num proto-name [buflen]\n", argv[0]);
                   exit(EXIT_FAILURE);
               }
    
               port = htons(atoi(argv[1]));
               protop = (strcmp(argv[2], "null") == 0 ||
                         strcmp(argv[2], "NULL") == 0) ?  NULL : argv[2];
    
               buflen = 1024;
               if (argc > 3)
                   buflen = atoi(argv[3]);
    
               if (buflen > MAX_BUF) {
                   printf("Exceeded buffer limit (%d)\n", MAX_BUF);
                   exit(EXIT_FAILURE);
               }
    
               erange_cnt = 0;
                           printf("Exceeded buffer limit (%d)\n", MAX_BUF);
                           exit(EXIT_FAILURE);
                       }
                   }
               } while (s == ERANGE);
    
               printf("getservbyport_r() returned: %s  (buflen=%d)\n",
                       (s == 0) ? "0 (success)" : (s == ENOENT) ? "ENOENT" :
                       strerror(s), buflen);
    
               if (s != 0 || result == NULL) {
                   printf("Call failed/record not found\n");
                   exit(EXIT_FAILURE);
               }
    
               printf("s_name=%s; s_proto=%s; s_port=%d; aliases=",
                           result_buf.s_name, result_buf.s_proto,
                           ntohs(result_buf.s_port));
               for (p = result_buf.s_aliases; *p != NULL; p++)
                   printf("%s ", *p);
               printf("\n");
    
               exit(EXIT_SUCCESS);
           }
    
    
    

    SEE ALSO

           getservent(3), services(5)
    
    
    

    GNU 2010-09-10 GETSERVENT_R(3)

    
    
  • MORE RESOURCE


  • Linux

    The Distributions





    Linux

    The Software





    Linux

    The News



  • MARKETING






  • Toll Free

webmaster@linuxguruz.com
Copyright © 1999 - 2016 by LinuxGuruz