Using the serviceentry class

- Introduction
- Lookup By Name
- Lookup By Number

### Introduction

The serviceentry class provides methods for retrieving network service definitions. These are usually defined in a file like /etc/services on unix-like systems or C:\Windows\System32\drivers\etc\services on Windows, or are served from another source via the name-service switch.

Services can be looked up by name or number.

### Lookup By Name

In this example, information for the "smtp" service, "tcp" protocol is retrieved.

> // Copyright (c) 2003 David Muse
> // See the file COPYING for more information
> #include <rudiments/serviceentry.h>
> #include <rudiments/stdio.h>
> int main(int argc, const char **argv) {
> // get the service information for "smtp","tcp" protocol
> serviceentry se;
> se.initialize("smtp","tcp");
> // print out details
> stdoutput.printf(" Name: %s\n",se.getName());
> stdoutput.printf(" Port: %d\n",se.getPort());
> stdoutput.printf(" Protocol: %s\n",se.getProtocol());
> stdoutput.printf(" Alias list:\n");
> for (uint32_t i=0; se.getAliasList() && se.getAliasList()[i]; i++) {
> stdoutput.printf(" %s\n",se.getAliasList()[i]);
> }
> }

### Lookup By Number

In this example, information for "service number 25", "tcp" protocol is retrieved.

> // Copyright (c) 2003 David Muse
> // See the file COPYING for more information
> #include <rudiments/serviceentry.h>
> #include <rudiments/stdio.h>
> int main(int argc, const char **argv) {
> // get the service information for the service
> // that would run on port 25, "tcp" protocol
> serviceentry se;
> se.initialize(25,"tcp");
> // print out details
> stdoutput.printf(" Name: %s\n",se.getName());
> stdoutput.printf(" Port: %d\n",se.getPort());
> stdoutput.printf(" Protocol: %s\n",se.getProtocol());
> stdoutput.printf(" Alias list:\n");
> for (uint32_t i=0; se.getAliasList() && se.getAliasList()[i]; i++) {
> stdoutput.printf(" %s\n",se.getAliasList()[i]);
> }
> }