下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
| Constant | Value | Description |
|---|---|---|
FUNCTION_TRACE
(integer)
|
1 | |
ARGS_TRACE
(integer)
|
2 | |
ASSIGNMENT_TRACE
(integer)
|
4 | |
STATEMENT_TRACE
(integer)
|
8 | |
MEMORY_TRACE
(integer)
|
16 | |
TIMING_TRACE
(integer)
|
32 | |
SUMMARY_TRACE
(integer)
|
64 | |
ERROR_TRACE
(integer)
|
128 | |
PROF_TRACE
(integer)
|
256 | |
APD_VERSION
(string)
|
example: 1.0.2-dev |