diff options
author | Glenn Randers-Pehrson <glennrp at users.sourceforge.net> | 2011-11-21 17:05:41 -0600 |
---|---|---|
committer | Glenn Randers-Pehrson <glennrp at users.sourceforge.net> | 2011-11-21 17:05:41 -0600 |
commit | 680da02ade3d8f9abcb7bcd3d41e66e8e1187d0a (patch) | |
tree | 8f2f171e036df8eadc081250099bd084a8a22895 /png.h | |
parent | 8e836313612ab7a2e6b43c23d017c66ecaaffea0 (diff) | |
download | libpng-680da02ade3d8f9abcb7bcd3d41e66e8e1187d0a.tar.gz |
[libpng15] Updated the documentation of the png_text structure
(clarifying that the "lang" and "lang_key" fields can be NULL pointers
or might not exist).
Diffstat (limited to 'png.h')
-rw-r--r-- | png.h | 15 |
1 files changed, 11 insertions, 4 deletions
@@ -609,11 +609,18 @@ typedef png_sPLT_t FAR * FAR * png_sPLT_tpp; #ifdef PNG_TEXT_SUPPORTED /* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file, * and whether that contents is compressed or not. The "key" field - * points to a regular zero-terminated C string. The "text", "lang", and - * "lang_key" fields can be regular C strings, empty strings, or NULL pointers. + * points to a regular zero-terminated C string. The "text" fields can be a + * regular C string, an empty string, or a NULL pointer. * However, the structure returned by png_get_text() will always contain - * regular zero-terminated C strings (possibly empty), never NULL pointers, - * so they can be safely used in printf() and other string-handling functions. + * the "text" field as a regular zero-terminated C string (possibly + * empty), never a NULL pointer, so it can be safely used in printf() and + * other string-handling functions. Note that the "itxt_length", "lang", and + * "lang_key" members of the structure only exist when the library is built + * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by + * default without iTXt support. Also note that when iTXt *is* supported, + * the "lang" and "lang_key" fields contain NULL pointers when the + * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or + * PNG_TEXT_COMPRESSION_zTXt. */ typedef struct png_text_struct { |