All uniform locations are "-1" on MacOS X

Question

I am experiencing really weird bug.I am porting some OpenGL codebase to MacOS X 10.7.5 The OpenGL code is suited for GL3.2 version.Original version (on Windows/Linux") works fine.No errors in GLSL or OpenGL side.But on Mac, when trying to access the uniforms all the locations are "-1".It is problematic to put out here the whole code as it is wrapped into framework(also I am sure 100% it is written correctly as it was tested to great extent on other platforms),but here is some of GLSL code:

#version 150 core
uniform sampler2D tex;  
uniform vec2 dir;  
uniform float cont;
noperspective in vec2 uv;
out vec4 colorOut;  
void main(){
...

All the uniforms are in use by the shader so it is unlikely that GLSLcompiler optimizes them out.

UPDATE:

Ok,I have some advance in pinning down the problem.Somehow, it seems that the character string, I pass to a method which retrieves uniform location,gets truncated.Here is the test:

Explicit call to :

GLuint loc1 = glGetUniformLocation(shaderEmboss->getHandle(), "dir");

returns the location al right.

But if I pass the location name as param "const GLchar* name" , I can see in the XCode debugger only the first char of the string.

Answer 1

First thanks to @umlum for debug help.I managed to pin down the issue.It has to do with multiple OpenGL context.My program is plugin in Adobe AfterEffect(AE).AE during runtime spawns its own contexts at will.In my code each time I render OpenGL stuff I was enabling my context like this (MaxOS X):

   _context = CGLGetCurrentContext() ;
    CGLSetCurrentContext(_context);

Calling the first line appeared to be grave mistake!What happens (probably) is that at the time I am trying to access the (supposedly mine) current context, it is already not my context but one of AE contexts which the program manages independently. _context = CGLGetCurrentContext() - I commented this line and it seems to be working now. I figured it all out by using

glGetActiveUniform()

Running it I found that my shader program contains uniform names which it doesn't really have.So it became apparent that my program's handle probably references a program from different context.