getnetconfig(3N)

DESCRIPTION

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

getnetconfig() returns a pointer to the current entry in the netconfig database, formatted as a struct netconfig. Successive calls will return successive netconfig entries in the netconfig database. getnetconfig() can be used to search the entire netconfig file. getnetconfig() returns NULL at the end of the file. handlep is the handle obtained through setnetconfig().

A call to setnetconfig() has the effect of "binding" to 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().

endnetconfig() should be called when processing is complete to release resources for reuse. handlep is the handle obtained through setnetconfig(). 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().

getnetconfigent() returns a pointer to the struct netconfig structure corresponding to netid. It returns NULL if netid is invalid (that is, does not name an entry in the netconfig database).

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 the 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, will return a pointer to a string that contains the error message.

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

MULTITHREAD USAGE

These functions can be called safely in a multithreaded environment. They may be cancellation points in that they call functions that are cancel points.

In a multithreaded environment, these functions are not safe to be called by a child process after fork() and before exec(). These functions should not be called by a multithreaded application that supports asynchronous cancellation or asynchronous signals.

RETURN VALUE

setnetconfig() returns a unique handle to be used by getnetconfig(). In the case of an error, setnetconfig() returns NULL and nc_perror() or nc_sperror() can be used to print the reason for failure.

getnetconfig() returns a pointer to the current entry in the netconfig() database, formatted as a struct netconfig. getnetconfig() returns NULL at the end of the file, or upon failure.

endnetconfig() returns 0 on success and -1 on failure (for example, if setnetconfig() was not called previously).

On success, getnetconfigent() returns a pointer to the struct netconfig structure corresponding to netid; otherwise it returns NULL.

nc_sperror() returns a pointer to a buffer which contains the error message string. This buffer is overwritten on each call. In multithreaded applications, this buffer is implemented as thread-specific data.

SEE ALSO

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