[Git][freetype/freetype][master] doc: Clarify description of `FT_Stream_IoFunc`.

[Werner Lemberg (@wl)]

Werner Lemberg pushed to branch master at FreeType / FreeType

Commits:

• d5d048bb
  by Stephen Holdaway at 2022-07-06T12:55:40+02:00

  doc: Clarify description of `FT_Stream_IoFunc`.
  
  The existing documentation comments on `FT_Stream_IoFunc` hinted at the dual
  seek/read behavior required for custom stream implementations to work, but
  it didn't explicitly explain it.  Without looking at the internals of
  FreeType, it was easy for someone to assume their implementation should
  handle both seek and read operations all the time.  If this is done, you get
  a variety of errors, but mostly just `Unknown_File_Format` (error code
  0x02).
  

1 changed file:

• include/freetype/ftsystem.h

Changes:

include/freetype/ftsystem.h

---

...	...	@@ -229,7 +229,8 @@ FT_BEGIN_HEADER
229	229	* A handle to the source stream.
230	230	*
231	231	* offset ::
232		- * The offset of read in stream (always from start).
	232	+ * The offset from the start of the stream to seek to if this is a seek
	233	+ * operation (see note).
233	234	*
234	235	* buffer ::
235	236	* The address of the read buffer.
...	...	@@ -241,8 +242,13 @@ FT_BEGIN_HEADER
241	242	* The number of bytes effectively read by the stream.
242	243	*
243	244	* @note:
244		- * This function might be called to perform a seek or skip operation with
245		- * a `count` of~0. A non-zero return value then indicates an error.
	245	+ * This function performs a seek *or* a read operation depending on the
	246	+ * argument values. If `count` is zero, the operation is a seek to
	247	+ * `offset` bytes. If `count` is >~0, the operation is a read of `count`
	248	+ * bytes from the current position in the stream, and the `offset` value
	249	+ * should be ignored.
	250	+ *
	251	+ * For seek operations, a non-zero return value indicates an error.
246	252	*
247	253	*/
248	254	typedef unsigned long

—
View it on GitLab.
You're receiving this email because of your account on gitlab.freedesktop.org. If you'd like to receive fewer emails, you can adjust your notification settings.