Stack trace
In computing, a stack trace (also called stack backtrace or stack traceback) is a report of the active stack frames at a certain point in time during the execution of a program.
Programmers commonly use stack tracing during interactive and post-mortem debugging. End-users may see a stack trace displayed as part of an error message, which the user can then report to a programmer.
A stack trace allows tracking the sequence of nested functions called - up to the point where the stack trace is generated. In a post-mortem scenario this extends up to the function where the failure occurred (but was not necessarily caused). Sibling function calls do not appear in a stack trace.
As an example, the following Python program contains an error.
def a(): b() def b(): c() def c(): error() a()
Running the program under the standard Python interpreter produces the following error message.
Traceback (most recent call last):
File "tb.py", line 10, in <module>
a()
File "tb.py", line 2, in a
b()
File "tb.py", line 5, in b
c()
File "tb.py", line 8, in c
error()
NameError: global name 'error' is not defined
The stack trace shows where the error occurs, namely in the c function. It also shows that the c function was called by b, which was called by a, which was in turn called by the code on line 10 (the last line) of the program.
Language support
Most programming languages, including Java and C#, have built-in support for retrieving the current stack-trace via system calls. C++ has no built-in support for doing this, but C++ users can retrieve stack traces with (for example) the stacktrace library.