FBO always 0 in native plugin IOS

Hi,

I'm making a Native unity plugin in IOS which is reading a Unity RenderTexture in my native code.

I used the Unity events as describe in the documentation.

In my plugin I simple made this code :

     //Init
     glGenFramebuffers(1, &_fbo);
     glBindBuffer(GL_FRAMEBUFFER, _fbo);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textureID, 0);
     glBindFramebuffer(GL_FRAMEBUFFER, 0);

     // Reading
     glBindFramebuffer(GL_FRAMEBUFFER, _fbo);
     glClear(0);
     glReadPixels(0, 0, _width, _height, GL_RGBA, GL_UNSIGNED_BYTE, _pixels);
     glBindFramebuffer(GL_FRAMEBUFFER, 0);

This is a simple code but the fbo is always set to 0, so I am not able to read my texture.

Can you help me please ?