NAME

getnetconfig − get network configuration database entry

SYNOPSIS

#include <netconfig.h>
void ∗setnetconfig(void);
struct netconfig ∗getnetconfig(void ∗handlep);
int endnetconfig(void ∗handlep);
struct netconfig ∗getnetconfigent(char ∗netid);
void freenetconfigent(struct netconfig ∗netconfigp);
void nc_perror (char ∗msg);
char ∗nc_sperror (void);

DESCRIPTION

The five library routines described on this page are part of the UNIX System V Network Selection component.  They provide application access to the system network configuration database, /etc/netconfig.  In addition to the netconfig database and the routines for accessing it, Network Selection includes the environment variable NETPATH [see environ(5)] and the NETPATH access routines described in getnetpath(3N). 

A call to setnetconfig has the effect of “binding” or “rewinding” the netconfig database.  setnetconfig must be called before the first call to getnetconfig and may be called at any other time.  setnetconfig need not be called before a call to getnetconfigent.  setnetconfig returns a unique handle to be used by getnetconfig.  In the case of an error, setconfig returns NULL and nc_perror or nc_sperror can be used to print the reason for failure. 

When first called, getnetconfig returns a pointer to the current entry in the netconfig database, formatted as a netconfig structure.  getnetconfig can thus be used to search the entire netconfig file.  getnetconfig returns NULL at end of file. 

endnetconfig should be called when processing is complete to release resources for reuse.  Programmers should be aware, however, that the last call to ­endnetconfig frees all memory allocated by getnetconfig for the struct ­netconfig data structure.  endnetconfig may not be called before ­setnetconfig.  endnetconfig returns 0 on success and −1 on failure (for example, if setnetconfig was not called previously). 

getnetconfigent returns a pointer to the netconfig structure corresponding to netid.  It returns NULL if netid is invalid (that is, does not name an entry in the netconfig database).  It returns NULL and sets errno in case of failure (for example, if setnetconfig was not called previously). 

freenetconfigent frees the netconfig structure pointed to by netconfigp, ­previously returned by getnetconfigent. 

nc_perror prints a message to the standard error indicating why any of the above routines failed.  The message is prepended with string msg and a colon.  A NEWLINE is appended at the end of the message. 

nc_sperror is similar to nc_perror but instead of sending the message to the standard error indicating why the network selection routines failed, it returns the string which contains the message:

Warning: It returns pointer to static data that is overwritten on each call.

nc_perror and nc_sperror can also be used with the NETPATH access routines defined in getnetpath(3N). 

SEE ALSO

netconfig(4), getnetpath(3N), and environ(5). 

  —  Networking Support Utilities