SDL_Image and IMG_Init(0) not as expected

The documentation for IMG_Init states: “You may call this function with a 0 to
retrieve whether support was built-in or not loaded yet.”

What does this statement mean? I had assumed this to mean that calling IMG_Init
(0) will return the current status of JPG, PNG or TIF support. However looking
at the source, IMG_Init(0) will always return 0 as flags is bitwise ANDed
with IMG_INIT_JPG/IMG_INIT_PNG/IMG_INIT_TIF.

int IMG_Init(int flags)
73 {
74 int result = 0;
75
76 if (flags & IMG_INIT_JPG) {
77 if ((initialized & IMG_INIT_JPG) || IMG_InitJPG() == 0)
{
78 result |= IMG_INIT_JPG;
79 }
80 }
81 if (flags & IMG_INIT_PNG) {
82 if ((initialized & IMG_INIT_PNG) || IMG_InitPNG() == 0)
{
83 result |= IMG_INIT_PNG;
84 }
85 }
86 if (flags & IMG_INIT_TIF) {
87 if ((initialized & IMG_INIT_TIF) || IMG_InitTIF() == 0)
{
88 result |= IMG_INIT_TIF;
89 }
90 }
91 initialized |= result;
92
93 return (result);
94 }