Conoscere lo stato di un lettore CD con le funzioni del API di libcdio
Da Gambas-it.org - Wikipedia.
La libreria Libcdio consente di gestire i CD ed i relativi driver presenti nel sistema.
Per utilizzare le funzioni esterne del API di libcdio sarà necessario richiamare l'attuale libreria: "libcdio.so.18.0.0".
Mostriamo un semplice codice che consentirà di sapere se lo stato del lettore CD è mutato o no; ossia se è stato appena inserito un CD oppure se è stato appena estratto.
Private p_cdio As Pointer
Library "libcdio:18.0.0"
Private Enum DRIVER_UNKNOWN = 0, DRIVER_AIX, DRIVER_FREEBSD, DRIVER_NETBSD, DRIVER_LINUX, DRIVER_SOLARIS,
DRIVER_OSX, DRIVER_WIN32, DRIVER_CDRDAO, DRIVER_BINCUE, DRIVER_NRG, DRIVER_DEVICE
' CdIo_t * cdio_open (const char *psz_source, driver_id_t driver_id)
' Sets up to read from place specified by psz_source and driver_id.
Private Extern cdio_open(psz_source As String, driver_id As Integer) As Pointer
' int cdio_get_media_changed(CdIo_t * p_cdio)
' Find out if media has changed since the last call.
Private Extern cdio_get_media_changed(cdioP As Pointer) As Integer
' void cdio_destroy(CdIo_t * p_cdio)
' Free any resources associated with p_cdio.
Private Extern cdio_destroy(cdioP As Pointer)
Public Sub Form_Open()
p_cdio = cdio_open(Null, DRIVER_UNKNOWN)
If p_cdio = 0 Then Error.Raise("Impossibile trovare il driver per il CD !")
If cdio_get_media_changed(p_cdio)
Print "Stato iniziale del lettore CD: cambiato"
Else
Print "Stato iniziale del lettore CD: non cambiato"
Endif
End
Public Sub Button1_Click()
If cdio_get_media_changed(p_cdio)
Print "Stato attuale del lettore CD: cambiato"
Else
Print "Stato attuale del lettore CD: non cambiato"
Endif
End
Public Sub Button2_Click()
' Va in chiusura:
cdio_destroy(p_cdio)
Quit
End
In quest'altro esempio si verificherà oltre allo stato del drive, come nel precedente codice, anche se esso è chiuso oppure aperto:
Library "libcdio:18.0.0"
Private Enum DRIVER_UNKNOWN = 0, DRIVER_AIX, DRIVER_FREEBSD, DRIVER_NETBSD, DRIVER_LINUX, DRIVER_SOLARIS,
DRIVER_OSX, DRIVER_WIN32, DRIVER_CDRDAO, DRIVER_BINCUE, DRIVER_NRG, DRIVER_DEVICE
Private Enum CDIO_MMC_R_W_ERROR_PAGE = &01, CDIO_MMC_WRITE_PARMS_PAGE = &05, CDIO_MMC_CDR_PARMS_PAGE = &0d, CDIO_MMC_AUDIO_CTL_PAGE = &0e,
CDIO_MMC_POWER_PAGE = &1a, CDIO_MMC_FAULT_FAIL_PAGE = &1c, CDIO_MMC_TO_PROTECT_PAGE = &1d, CDIO_MMC_CAPABILITIES_PAGE = &2a, CDIO_MMC_ALL_PAGES = &3
' char* cdio_get_default_device_driver(driver_id_t * p_driver_id)
' Return a string containing the default CD device if none is specified.
Private Extern cdio_get_default_device_driver(p_driver_id As Pointer) As String
' CdIo_t * cdio_open (const char *psz_source, driver_id_t driver_id)
' Sets up to read from place specified by psz_source and driver_id.
Private Extern cdio_open(psz_source As String, driver_id As Integer) As Pointer
' int mmc_get_tray_status(const CdIo_t * p_cdio)
' Find out if media tray is open or closed.
Private Extern mmc_get_tray_status(cdioP As Pointer) As Integer
' const char* cdio_driver_errmsg(driver_return_code_t drc)
' Returns the string information about drc.
Private Extern cdio_driver_errmsg(drc As Integer) As String
' int mmc_get_media_changed(const CdIo_t * p_cdio)
' Find out if media has changed since the last call.
Private Extern mmc_get_media_changed(cdioP As Pointer) As Integer
' void cdio_destroy(CdIo_t * p_cdio)
' Free any resources associated with p_cdio.
Private Extern cdio_destroy(cdioP As Pointer)
Public Sub Main()
Dim p_cdio As Pointer
Dim dd, ret As Integer
Dim psz_drive As String
dd = DRIVER_DEVICE
psz_drive = cdio_get_default_device_driver(VarPtr(dd))
If IsNull(psz_drive) Then
Error.Raise("-- Can't find a CD-ROM !")
Else
Print "Il 'driver' predefinito è: "; psz_drive
Endif
p_cdio = cdio_open(Null, DRIVER_UNKNOWN)
If p_cdio = 0 Then Error.Raise("Impossibile trovare il driver per il CD !")
ret = mmc_get_tray_status(p_cdio)
Select Case ret
Case 0
Print "-- Il drive CD-ROM '"; psz_drive; "' è chiuso."
Case 1
Print "-- Il drive CD-ROM '"; psz_drive; "' è aperto."
Case Else
Error.Raise("Errore relativo al drive " & psz_drive & "':" & cdio_driver_errmsg(ret) & ".")
End Select
ret = mmc_get_media_changed(p_cdio)
Select Case ret
Case 0
Print "-- Il drive CD-ROM '"; psz_drive; "' non è cambiato dall'ultimo controllo."
Case 1
Print "-- Il drive CD-ROM '"; psz_drive; "' è cambiato dall'ultimo controllo."
Case Else
Error.Raise("Errore relativo al drive " & psz_drive & "':" & cdio_driver_errmsg(ret) & ".")
End Select
' Va in chiusura:
cdio_destroy(p_cdio)
End
In questo terzo esempio si verificherà semplicemente se nel lettore DC-DVD è presente un disco:
Library "libcdio:18.0.0"
Private Enum DRIVER_UNKNOWN = 0, DRIVER_AIX, DRIVER_FREEBSD, DRIVER_NETBSD, DRIVER_LINUX, DRIVER_SOLARIS,
DRIVER_OSX, DRIVER_WIN32, DRIVER_CDRDAO, DRIVER_BINCUE, DRIVER_NRG, DRIVER_DEVICE
Private Const CDIO_DISC_MODE_ERROR As Integer = 17
' CdIo_t * cdio_open (const char *psz_source, driver_id_t driver_id)
' Sets up to read from place specified by psz_source and driver_id.
Private Extern cdio_open(psz_source As String, driver_id As Integer) As Pointer
' discmode_t cdio_get_discmode (CdIo_t *p_cdio)
' Get disc mode - the kind of CD (CD-DA, CD-ROM mode 1, CD-MIXED, etc. that we've got.
Private Extern mmc_get_tray_status(cdioP As Pointer) As Integer
' void cdio_destroy(CdIo_t * p_cdio)
' Free any resources associated with p_cdio.
Private Extern cdio_destroy(cdioP As Pointer)
Public Sub Main()
Dim p_cdio As Pointer
p_cdio = cdio_open(Null, DRIVER_UNKNOWN)
If p_cdio = 0 Then Error.Raise("Impossibile trovare il file-device del driver CD/DVD !")
' Verifica se nel lettore CD-DVD è presente un disco:
If cdio_get_discmode(p_cdio) = CDIO_DISC_MODE_ERROR Then Print "Non è presente nel lettore CD-DVD alcun disco !"
' Va in chiusura:
cdio_destroy(p_cdio)
End
