packfile_password(3)            Allegro manual            packfile_password(3)



NAME
       packfile_password - Sets the global I/O encryption password. Allegro
       game programming library.

SYNOPSIS
       #include <allegro.h>


       void packfile_password(const char *password);

DESCRIPTION
       Sets the encryption password to be used for all read/write operations
       on files opened in future using Allegro's packfile functions (whether
       they are compressed or not), including all the save, load and config
       routines. Files written with an encryption password cannot be read
       unless the same password is selected, so be careful: if you forget the
       key, nobody can make your data come back again! Pass NULL or an empty
       string to return to the normal, non-encrypted mode. If you are using
       this function to prevent people getting access to your datafiles, be
       careful not to store an obvious copy of the password in your
       executable: if there are any strings like "I'm the password for the
       datafile", it would be fairly easy to get access to your data :-)

       Note #1: when writing a packfile, you can change the password to
       whatever you want after opening the file, without affecting the write
       operation.  On the contrary, when writing a sub-chunk of a packfile,
       you must make sure that the password that was active at the time the
       sub-chunk was opened is still active before closing the sub-chunk. This
       is guaranteed to be true if you didn't call the packfile_password()
       routine in the meantime. Read operations, either on packfiles or sub-
       chunks, have no such restriction.

       Note #2: as explained above, the password is used for all read/write
       operations on files, including for several functions of the library
       that operate on files without explicitly using packfiles (e.g.
       load_bitmap()).  The unencrypted mode is mandatory in order for those
       functions to work.  Therefore remember to call packfile_password(NULL)
       before using them if you previously changed the password. As a rule of
       thumb, always call packfile_password(NULL) when you are done with
       operations on packfiles.  The only exception to this is custom
       packfiles created with pack_fopen_vtable().


SEE ALSO
       pack_fopen(3), load_datafile(3), pack_fopen_vtable(3)



Allegro                          version 4.2.3            packfile_password(3)
