Question

In my program I put this code for instructs program to spawn a command. This can be used to start another program using a key in my program, such as to spawn firefox. Using program-command run_command “firefox” will have program call system( “firefox &” ).

    case RUN_COMMAND:
        if( arg ) {
            char commandline[ 256 ];
            snprintf( commandline, sizeof (commandline), "%s &", arg );
            if( cmd->screen ) {
                char message[ 256 ];
                snprintf( message, sizeof (message), _("Running: %s"), arg );
                screen_show_message( cmd->screen, message );
            }
            system( commandline );
        }
        break;

When I compile it give this error:

warning: ignoring return value of 'system', declared with attribute warn_unused_result [-Wunused-result]

Answer 1

It means that you shouldn’t assume that system will always succeed. Your code becomes unreliable this way. Appropriate error handling should be in place.