Manual

VK_NO_STDDEF_H

Control definition of <stddef.h> types

If the VK_NO_STDDEF_H macro is defined by the application at compile time, size_t, must also be defined by the application. Otherwise, the Vulkan headers will not compile. If VK_NO_STDDEF_H is not defined, the system <stddef.h> is used to define this type.