NAME

AG_Core — agar core library initialization

SYNOPSIS

#include <agar/core.h>

DESCRIPTION

The Agar-Core library implements the AG_Object(3) system and provides interfaces to common operating system services (filesystems, network APIs, threads, etc). Agar-GUI is built on top of AG_Core, but Agar-Core itself contains no GUI-related code and may be installed independently.

For a complete listing of available subsystems and interfaces, see the “AGAR-CORE” section of AG_Intro(3).

INITIALIZATION

int
AG_InitCore(const char *progname, Uint flags);

void
AG_AtExitFunc(void (*fn)(void));

void
AG_Quit(void);

void
AG_Destroy(void);

The AG_InitCore() function initializes the AG_Core library. progname is an optional identifier for the program. This name may be used to construct platform-specific directory paths. Unless the AG_CREATE_DATADIR flags option is set, the progname argument can be NULL.

Available flags options include:

AG_VERBOSE

Allow errors/warnings on the standard error output.

AG_CREATE_DATADIR

Check that the application data directory exists, create it if necessary (or fail if it cannot be created). It contains the state of objects saved by AG_ObjectSave(3). The default is $HOME/.progname/ on Unix and platform-dependent elsewhere.

AG_SOFT_TIMERS

Don't use OS-provided timer mechanisms (such as BSD kqueue(2), Linux timerfd or select(2)). Timers will be handled either by explicitely updating a software-based timing wheel (see AG_ProcessTimeouts(3)), or some other mechanism.

AG_POSIX_USERS

If both AG_User(3) modules "getenv" and "posix" are available, prefer "posix". This is not the default because "posix" incurs potential startup overhead while initially accessing the password database (and $HOME is all Agar needs for its own purposes).

The AG_AtExitFunc() registers a function that will be invoked automatically by AG_Destroy().

AG_Quit() terminates the application by releasing resources allocated by AG_Core and invoking exit(2).

The AG_Destroy() function releases all resources allocated by the AG_Core library.

AGAR VERSION INFORMATION

void
AG_GetVersion(AG_AgarVersion *ver);

bool
AG_VERSION_ATLEAST(int major, int minor, int patchlevel);

The AG_GetVersion() function fills an AG_AgarVersion structure with version information:

typedef struct ag_agar_version {
	int major;
	int minor;
	int patch;
	const char *release;
} AG_AgarVersion;

Agar does not need to have been previously initialized for AG_GetVersion() to work.

The AG_VERSION_ATLEAST() macro evaluates to true if the current Agar version is equal to, or exceeds the given version number.

EXAMPLES

The following program initializes Agar-Core and prints the Agar version and release information:

int
main(int argc, char *argv[])
{
	AG_AgarVersion *ver;

	if (AG_InitCore("myProgram", 0) == -1) {
		AG_Verbose("AG_InitCore: %s\n", AG_GetError());
		return (1);
	}

	AG_GetVersion(&ver);
	AG_Verbose("Hello Agar %d.%d.%d (\"%s\")\n",
	    ver.major, ver.minor, ver.patch, ver.release);

	AG_Destroy()
	return (0);
}

SEE ALSO

AG_Config(3), AG_DataSource(3), AG_Db(3), AG_DSO(3), AG_Error(3), AG_Event(3), AG_EventLoop(3), AG_Execute(3), AG_File(3), AG_Intro(3), AG_Limits(3), AG_Net(3), AG_Object(3), AG_String(3), AG_TextElement(3), AG_Threads(3), AG_Time(3), AG_Timer(3), AG_User(3), AG_Variable(3), AG_Version(3)

HISTORY

The AG_InitCore() function first appeared in Agar 1.0. The AG_CREATE_DATADIR option appeared in Agar 1.3.3. AG_SOFT_TIMERS in Agar 1.5.0 and AG_POSIX_USERS in Agar 1.6.0.