Invalid Conversion

Invalid Conversion

Raf Vermeulen

Member #7,166

April 2006

I've got this here code (C++, Allegro and AGUP for the GUI) that's an utter bastard to get to work.

1 
2int translate()
3{
4    alert("You pushed my button!", "Isn't this a useful feature?", 0,
5          "&Yes", "&Definitely", 'y', 'd');
6 
7    return D_O_K;
8}
9 
10 
11 
12(...)
13 
14DIALOG main_dlg[] =
15{
16   /* (dialog proc)     (x)   (y)   (w)   (h) (fg)(bg) (key) (flags)     (d1) (d2)    (dp)                   (dp2) (dp3) */
17   
18   /* this element just clears the screen, therefore it should come before the others */
19   { d_agup_clear_proc,        0,   0,    0,    0,   0,  0,    0,      0,       0,   0,    NULL,                   NULL, NULL  },
20   
21 
22 
23   { d_agup_edit_proc,     100, 75, 160,  8,  0,  0,  0,  0,  LENGTH,   0,  word_1,     NULL,  NULL  },
24   { d_agup_push_proc,     100, 95, 100, 20,  0,  0,  0,  0,       0,   0,  str_trans,     0,  translate },
25   { quit_proc,              0,  0,   0,  0,  0,  0, 27,  0,       0,   0,       0,        0,  0 },
26   
27   /* the next two elements don't draw anything */
28   { d_yield_proc,        0,   0,    0,    0,   0,  0,    0,      0,       0,   0,    NULL,                   NULL, NULL  },
29   { NULL,                0,   0,    0,    0,   0,  0,    0,      0,       0,   0,    NULL,                   NULL, NULL  }
30};

What it does while compiling, is giving this error message:

Quote:

invalid conversion from `int (*)()' to `void*'

It points to the main_dlg declaration, and seems to be caused by the d_agup_push_proc part.

Now, I've checked an example code that does work:

1int surprise()
2{
3    alert("You pushed my button!", "Isn't this a useful feature?", 0,
4          "&Yes", "&Definitely", 'y', 'd');
5 
6    return D_O_K;
7}
8 
9(...)
10 
11#define DIS D_DISABLED
12#define SEL D_SELECTED
13 
14 
15DIALOG main_dlg[] =
16{
17    /* proc                   x     y     w    h   fg    bg    key  flags    d1    d2  dp                    dp2    dp3 */
18    { d_agup_clear_proc,      0,     0, 320, 240,  0,    0,    0,   0,       0,    0,  0,                    0,     0 },
19 
20    /* First column */
21    { d_agup_check_proc,        5,  25, 100,  12,  0,    0,    0,   SEL,     0,    0,  (void *)"check box",  0,     0 },
22    { d_agup_radio_proc,        5,  50, 100,  12,  0,    0,    0,   SEL,     1,    0,  (void *)"radio 1",    0,     0 },
23    { d_agup_radio_proc,        5,  75, 100,  12,  0,    0,    0,   0,       1,    0,  (void *)"radio 2",    0,     0 },
24    { d_agup_shadow_box_proc,   5, 100, 100,  20,  0,    0,    0,   0,       0,    0,  0,                    0,     0 },
25    { d_agup_slider_proc,       5, 125, 100,  12,  0,    0,    0,   0,       100, 50,  0,                    0,     0 },
26    { d_agup_edit_proc,         5, 150, 100,  14,  0,    0,    0,   0,       100,  0,  buf2,                 0,     0 },
27    { d_agup_list_proc,         5, 175, 100,  50,  0,    0,    0,   0,       2,    0,  lister,               sel2,  0 },
28 
29    /* Buttons */
30    { d_agup_button_proc,     110,  25, 100,  20,  0,    0,    0,   0,       0,    0,  (void *)"button",     0,     0 },
31    { d_agup_push_proc,       110,  50, 100,  20,  0,    0,    0,   0,       0,    0,  (void *)"button",     0,     surprise },
32    { d_agup_button_proc,     215,  25, 100,  20,  0,    0,    0,   DIS,     0,    0,  (void *)"button",     0,     0 },
33    { d_agup_button_proc,     215,  50, 100,  20,  0,    0,    0,   DIS|SEL, 0,    0,  (void *)"button",     0,     0 },
34 
35    /* Misc */
36    #define ICON_DIALOG 12
37    { d_agup_icon_proc,       240,  75,  50,  50,  0,    0,    0,   0,       2,    2,  0,                    0,     0 },
38    { d_agup_text_proc,       240, 130,  75,  12,  0,    0,    0,   0,       0,    0,  (void *)"A",          0,     0 },
39#if (ALLEGRO_VERSION == 4) && (ALLEGRO_SUB_VERSION == 0)
40    /* Allegro 4.0 had a severely broken ctext_proc. */
41    { d_agup_ctext_proc,      240 + 75 / 2, 150,  0,  12,  0,    0,    0,   0,       0,    0,  (void *)"B",          0,     0 },
42#else
43    { d_agup_ctext_proc,      240, 150,  75,  12,  0,    0,    0,   0,       0,    0,  (void *)"B",          0,     0 },    
44#endif
45    { d_agup_rtext_proc,      240, 170,  75,  12,  0,    0,    0,   0,       0,    0,  (void *)"C",          0,     0 },
46    { d_agup_textbox_proc,    110,  75, 100, 150,  0,    0,    0,   0,       0,    0,  buf3,                 0,     0 },
47    { d_agup_slider_proc,     215,  75,  12, 100,  0,    0,    0,   0,       100, 50,  0,                    0,     0 },
48    { d_agup_box_proc,        215, 185, 100,  20,  0,    0,    0,   0,       0,    0,  0,                    0,     0 },
49    { d_agup_slider_proc,     215, 213, 100,  12,  0,    0,    0,   DIS,     100,  0,  0,                    0,     0 },
50    { d_agup_menu_proc,         5,   5, 310,  12,  0,    0,    0,   0,       0,    0,  menubar,              0,     0 },
51    { quit_proc,              0,     0,   0,   0,  0,    0,    27,  0,       0,    0,  0,                    0,     0 },
52    { d_agup_text_proc,       0,   232, 320,   8,  0,    0,    0,   0,       0,    0,  version,              0,     0 },
53    { d_yield_proc,           0,     0,   0,   0,  0,    0,    0,   0,       0,    0,  0,                    0,     0 },
54    { NULL,                   0,     0,   0,   0,  0,    0,    0,   0,       0,    0,  0,                    0,     0 }
55};

That does work. I don't see what I've done wrong :? Anybody able to help me out on this one?

umperio

Member #3,474

April 2003

Try an explicit cast on both the string and procedure (void *).

sharpallegro - A C# Allegro wrapper
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Kitty Cat

Member #2,815

October 2002

C++ is a lot more strict on casting. Non-void pointers need to be cast to void* (in this case, the translate function pointer you're passing).

--
"Do not meddle in the affairs of cats, for they are subtle and will pee on your computer." -- Bruce Graham

Raf Vermeulen

Member #7,166

April 2006

That worked. Thanks so much, you two:)