[ft] Multithreading issues

[Iñaki Castillo Arteta]

 

I am using syncronization per font. That is to say, I do not reenter the library for the same font. I thought (mistakenly) that his would enough to prevent problems.

However, apparently the Freetype library does not support being called from two threads a the same time when the same  FT_Library is used.

 

One case for example when problems happen occurs when calling FT_Render_Glyph and FT_Load_Glyph from two different threads, for two different fonts, loaded with the same library handle.

 

As I use a local cache por bitmaps I rarely see the problem but it happens from time to time.

 

I have read here that Freetype does not used global variables. Am I right? So I assume it all should work fine provided I use one library handle per thread.

My goal is being able to enter the library from two different threads, without serialization.

 

How do you deal with this issue? Do you use several library handles or do you use serialization/synhronization to enter the library ?

 

Inaki.