DJ's GNU Programming Platform (DJGPP)[2] is a software development suite for Intel 80386-level and above, IBM PC compatibles which supports DOS operating systems.

[3] The compiler generates 32-bit code, which runs natively in 32-bit protected mode while switching back to 16-bit DOS calls for basic OS support.

However, unlike the Open Watcom C/C++ compiler, it is not a zero-based flat model due to preferring NULL pointer protection for better stability.

DJGPP presents the programmer an interface which is compatible with the ANSI C and C99 standards, DOS APIs, and an older POSIX-like environment.

While DJGPP runs in 32-bit protected mode, its stub and library heavily rely on many 16-bit DOS and BIOS calls.