Initialization

Detailed Description

Functions called during program startup.

Programs using the OLA libraries should call either ServerInit() or AppInit(). There are also extra functions to help with installing signal handlers and daemonizing a process.

Example

// For client applications
AppInit(argc, argv);
// For server applications
ServerInit(argc, argv, &export_map);

Files
file	Init.cpp
file	Init.h
	Functions called during program startup.

Functions
bool	ola::ServerInit (int argc, char *argv[], ExportMap *export_map)
	Used to initialize a server. More...
bool	ola::ServerInit (int *argc, char *argv[], ExportMap *export_map, const std::string &first_line, const std::string &description)
	Used to initialize a server. Installs the SEGV handler, initializes the random number generator and populates the export map. Also sets the help string for the program, parses flags and initialises logging from flags. More...
bool	ola::AppInit (int *argc, char *argv[], const std::string &first_line, const std::string &description)
	Used to initialize a application. Installs the SEGV handler and initializes the random number generator, sets the help string for the program, parses flags and initialises logging from flags. More...
bool	ola::NetworkInit ()
	Perform platform-specific initialization of the networking subsystem. More...
bool	ola::InstallSignal (int signal, void(*fp)(int signo))
	Install a signal handler. More...
bool	ola::InstallSEGVHandler ()
	Install signal handlers to deal with SIGBUS & SIGSEGV. More...
void	ola::InitExportMap (int argc, char *argv[], ExportMap *export_map)
	Populate the ExportMap with a couple of basic variables. More...
void	ola::Daemonise ()
	Run as a daemon. More...
void	ola::ClockInit ()
	Logs status of clock capabilities.

Function Documentation

AppInit()

bool ola::AppInit	(	int *	argc,
		char *	argv[],
		const std::string &	first_line,
		const std::string &	description
	)

Used to initialize a application. Installs the SEGV handler and initializes the random number generator, sets the help string for the program, parses flags and initialises logging from flags.

Parameters

argc	argument count
argv	pointer to the argument strings
first_line	the initial line that is displayed in the help section. This is displayed after argv[0].
description	a multiline description of the program

Returns

true on success and false otherwise

Note

If you are a server then call ServerInit() instead.

See also

ola::SetHelpString ola::ParseFlags ola::InitLoggingFromFlags

Daemonise()

void ola::Daemonise

(

)

Run as a daemon.

Daemonize logs messages if it fails, so it's best to initialize the logging system (ola::InitLogging) before calling. However Daemonize() closes all open file descriptors so stdout/stderr will point to /dev/null in the daemon process. Therefore daemons should always use syslog logging.

If we can't daemonize the process is terminated.

See logging.

See also

Logging

InitExportMap()

void ola::InitExportMap	(	int	argc,
		char *	argv[],
		ExportMap *	export_map
	)

Populate the ExportMap with a couple of basic variables.

Parameters

argc	argument count
argv	pointer to the argument strings
export_map	ExportMap to populate

This is called by ServerInit(). It sets the following variables:

• binary: name of the binary.
• cmd-line: command line used to start the binary
• fd-limit: the max number of file descriptors

InstallSEGVHandler()

bool ola::InstallSEGVHandler

(

)

Install signal handlers to deal with SIGBUS & SIGSEGV.

Returns

true on success and false otherwise

On receiving a SIGBUS or SIGSEGV a stack trace will be printed.

InstallSignal()

bool ola::InstallSignal	(	int	signal,
		void(*)(int signo)	fp
	)

Install a signal handler.

Parameters

signal	the signal number to catch
fp	is a function pointer to the handler

Returns

true on success and false otherwise

NetworkInit()

bool ola::NetworkInit

(

)

Perform platform-specific initialization of the networking subsystem.

This method is called by ServerInit() and AppInit(), so you only need to call this yourself if you're not using those.

Returns

true on success and false otherwise

ServerInit() [1/2]

bool ola::ServerInit	(	int	argc,
		char *	argv[],
		ExportMap *	export_map
	)

Used to initialize a server.

Parameters

argc	argument count
argv	pointer to argument strings
export_map	an optional pointer to an ExportMap

Returns

true on success and false otherwise

Note

If you are a client/application then call AppInit() instead.

This does the following:

• installs the SEGV handler
• initializes the random number generator
• sets the thread scheduling options
• populates the export map
• initializes the network stack (Windows only).

ServerInit() [2/2]

bool ola::ServerInit	(	int *	argc,
		char *	argv[],
		ExportMap *	export_map,
		const std::string &	first_line,
		const std::string &	description
	)

Used to initialize a server. Installs the SEGV handler, initializes the random number generator and populates the export map. Also sets the help string for the program, parses flags and initialises logging from flags.

Parameters

argc	argument count
argv	pointer to argument strings
export_map	an optional pointer to an ExportMap
first_line	the initial line that is displayed in the help section. This is displayed after argv[0].
description	a multiline description of the program

Returns

true on success and false otherwise

Note

If you are a client/application then call AppInit() instead.

See also

ola::SetHelpString ola::ParseFlags ola::InitLoggingFromFlags