Do uniform values remain in GLSL shader if unbound?

Question

I am writing a program that uses two different shaders for different primitives. My question is: if I bind a program, send it uniform variables, then use another shader prog

Answer 1

Yes, uniforms are specific to a program, and will be persistent if you unbind and rebind it.

Also, if you want, you could easily verify this yourself in that sample with glGetUniform.

From the OpenGL 4.1 Specification:

2.11.7 Uniform Variables

... Uniforms are program object-specific state. They retain their values once loaded, and their values are restored whenever a program object is used, as long as the program object has not been re-linked. ...