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std::basic_stacktrace

From cppreference.com
< cpp‎ | utility
 
 
Diagnostics library
 
 
Defined in header <stacktrace>
template< class Allocator >
class basic_stacktrace;
(1) (since C++23)
using stacktrace =
    std::basic_stacktrace<std::allocator <std::stacktrace_entry >>;
(2) (since C++23)
namespace pmr {

using stacktrace =
    std::basic_stacktrace<std::pmr::polymorphic_allocator <std::stacktrace_entry >>;

}
(3) (since C++23)
1) The basic_stacktrace class template represents a snapshot of the whole stacktrace or its given part. It satisfies the requirement of AllocatorAwareContainer, SequenceContainer, and ReversibleContainer, except that only move, assignment, swap, and operations for const-qualified sequence containers are supported, and the semantics of comparison functions are different from those required for a container.
2) Convenience type alias for the basic_stacktrace using the default std::allocator .
3) Convenience type alias for the basic_stacktrace using the polymorphic allocator.

The invocation sequence of the current evaluation \(\small{ {x}_{0} }\)x0 in the current thread of execution is a sequence \(\small{ ({x}_{0}, \dots, {x}_{n})}\)(x0, ..., xn) of evaluations such that, for \(\small{i \ge 0}\)i≥0, \(\small{ {x}_{i} }\)xi is within the function invocation \(\small{ {x}_{i+1} }\)xi+1.

A stacktrace is an approximate representation of an invocation sequence and consists of stacktrace entries.

A stacktrace entry represents an evaluation in a stacktrace. It is represented by std::stacktrace_entry in the C++ standard library.

Contents

[edit] Template parameters

Allocator - An allocator that is used to acquire/release memory and to construct/destroy the elements in that memory. The type must meet the requirements of Allocator. The program is ill-formed if Allocator::value_type is not std::stacktrace_entry.

[edit] Member types

Member type Definition
value_type std::stacktrace_entry
const_reference const value_type&
reference value_type&
const_iterator implementation-defined const LegacyRandomAccessIterator type that models random_access_iterator
iterator const_iterator
reverse_iterator std::reverse_iterator <iterator>
reverse_const_iterator std::reverse_iterator <const_iterator>
difference_type implementation-defined signed integer type
size_type implementation-defined unsigned integer type
allocator_type Allocator

[edit] Member functions

creates a new basic_stacktrace
(public member function) [edit]
destroys the basic_stacktrace
(public member function) [edit]
assigns to the basic_stacktrace
(public member function) [edit]
[static]
obtains the current stacktrace or its given part
(public static member function) [edit]
returns the associated allocator
(public member function) [edit]
Iterators
returns an iterator to the beginning
(public member function) [edit]
returns an iterator to the end
(public member function) [edit]
returns a reverse iterator to the beginning
(public member function) [edit]
returns a reverse iterator to the end
(public member function) [edit]
Capacity
checks whether the basic_stacktrace is empty
(public member function) [edit]
returns the number of stacktrace entries
(public member function) [edit]
returns the maximum possible number of stacktrace entries
(public member function) [edit]
Element access
access specified stacktrace entry
(public member function) [edit]
access specified stacktrace entry with bounds checking
(public member function) [edit]
Modifiers
swaps the contents
(public member function) [edit]

[edit] Non-member functions

compares the sizes and the contents of two basic_stacktrace values
(function template)
specializes the std::swap algorithm
(function template) [edit]
(C++23)
returns a string with a description of the basic_stacktrace
(function template) [edit]
(C++23)
performs stream output of basic_stracktrace
(function template) [edit]

[edit] Helper classes

hash support for std::basic_stacktrace
(class template specialization) [edit]
formatting support for basic_stacktrace
(class template specialization) [edit]

[edit] Notes

Support for custom allocators is provided for using basic_stacktrace on a hot path or in embedded environments. Users can allocate stacktrace_entry objects on the stack or in some other place, where appropriate.

The sequence of std::stacktrace_entry objects owned by a std::basic_stacktrace is immutable, and either is empty or represents a contiguous interval of the whole stacktrace.

boost::stacktrace::basic_stacktrace (available in Boost.Stacktrace) can be used instead when std::basic_stacktrace is not available.

Feature-test macro Value Std Feature
__cpp_lib_stacktrace 202011L (C++23) Stacktrace library
__cpp_lib_formatters 202302L (C++23) Formatting std::thread::id and std::stacktrace

[edit] Example

The output obtained using Compiler Explorer: msvc and gcc.

Run this code
#include <iostream>
#include <stacktrace>
 
int nested_func(int c)
{
 std::cout << std::stacktrace::current() << '\n';
 return c + 1;
}
 
int func(int b)
{
 return nested_func(b + 1);
}
 
int main()
{
 std::cout << func(777);
}

Possible output: 

// msvc output (the lines ending with '⤶' arrows are split to fit the width):
0> C:\Users\ContainerAdministrator\AppData\Local\Temp\compiler-explorer-compiler20221122-⤶
31624-2ja1sf.8ytzw\example.cpp(6): output_s!nested_func+0x1F
1> C:\Users\ContainerAdministrator\AppData\Local\Temp\compiler-explorer-compiler20221122-⤶
31624-2ja1sf.8ytzw\example.cpp(12): output_s!func+0x15
2> C:\Users\ContainerAdministrator\AppData\Local\Temp\compiler-explorer-compiler20221122-⤶
31624-2ja1sf.8ytzw\example.cpp(15): output_s!main+0xE
3> D:\a\_work1円\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl(288): output_s!⤶
__scrt_common_main_seh+0x10C
4> KERNEL32!BaseThreadInitThunk+0x14
5> ntdll!RtlUserThreadStart+0x21
779
 
gcc output:
 0# nested_func(int) at /app/example.cpp:7
 1# func(int) at /app/example.cpp:13
 2# at /app/example.cpp:18
 3# at :0
 4# at :0
 5# 
 
779

[edit] See also

representation of an evaluation in a stacktrace
(class) [edit]

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