install_allegro man page

install_allegro — Initialise the Allegro library.


#include <allegro.h>

int install_allegro(int system_id, int *errno_ptr, int (*atexit_ptr)());


Initialises the Allegro library. You must call either this or  allegro_init() before doing anything other than using the Unicode  routines. If you want to use a text mode other than UTF-8, you can set it with set_uformat() before you call this. The other functions that can be called before this one will be marked explicitly in the documentation, like set_config_file().

The available system ID codes will vary from one platform to another, but you will almost always want to pass SYSTEM_AUTODETECT. Alternatively, SYSTEM_NONE installs a stripped down version of Allegro that won't even try to touch your hardware or do anything platform specific: this can be useful for situations where you only want to manipulate memory bitmaps, such as the text mode datafile tools or the Windows GDI interfacing functions.

The `errno_ptr' and `atexit_ptr' parameters should point to the errno variable and atexit function from your libc: these are required because when Allegro is linked as a DLL, it doesn't have direct access to your local libc data. `atexit_ptr' may be NULL, in which case it is your responsibility to call allegro_exit() manually. Example:

   install_allegro(SYSTEM_AUTODETECT, &errno, atexit);

Return Value

This function returns zero on success and non-zero on failure (e.g. no system driver could be used). Note: in previous versions of Allegro this function would abort on error.

See Also

allegro_init(3), allegro_exit(3), set_uformat(3), set_config_file(3)

Referenced By

allegro_exit(3), allegro_init(3), allegro_message(3).

version 4.4.2 Allegro manual