The propietary environment built by QNX Software Systems is called Photon MicroGUI.
QNX provides the Qcc and qcc compilers. They are based on the POSIX c86 utility. By default Qcc considers a C++ program while qcc considers a C program.
It is important to know that QNX provides a command that allows to built a scaled embedded systems. This utility is named mkifs.
It is possible to do cross development (host-target) and stand alone development, that is, use the same computer to compile and run/test the embedded system.
The main programming languages are C and C++.
Moreover, QNX provides the Visual Age Micro-Edition environment to develop programs written using the java languaje.
Finally, QNX provides a tool called the Photon Application Builder (abbreviated as PhAB or AppBuilder). It's a visual tool to develop user's interface. The code generated by this tool is C and C++.
POSIX 1003.1.