A dbg(...) macro for C++
source link: https://www.tuicool.com/articles/yEVBbqr
Go to the source link to view the article. You can view the picture content, updated content and better typesetting reading experience. If the link is broken, please click the button below to view the snapshot at that time.
dbg(…)
A macro for printf
-style debugging fans.
Debuggers are great. But sometimes you just don't have the time and nerve to set up everything correctly and just want a quick way to inspect some values at runtime.
This projects provides a single header file with a dbg(…)
macro that can be used in all circumstances where you would typically write printf("…", …)
or std::cout << …
, but with a few extras.
Examples
#include <vector> #include <dbg.h> // You can use "dbg(..)" in expressions: int factorial(int n) { if (dbg(n <= 1)) { return dbg(1); } else { return dbg(n * factorial(n - 1)); } } int main() { std::string message = "hello"; dbg(message); // [example.cpp:15 (main)] message = "hello" (std::string) const int a = 2; const int b = dbg(3 * a) + 1; // [example.cpp:18 (main)] 3 * a = 6 (int) std::vector<int> numbers{b, 13, 42}; dbg(numbers); // [example.cpp:21 (main)] numbers = {7, 13, 42} (size: 3) (std::vector<int>) dbg("this line is executed"); // [example.cpp:23 (main)] this line is executed factorial(4); return 0; }
The code above produces this output ( try it yourself ):
Features
std::optional dbg.h
Installation
To make this actually usable, the dbg.h
header should to be available from all kinds of different places and in all kinds of environments. The quick & dirty way is to actually copy the header file to /usr/include
or to clone the repository and symlink dbg.h
to /usr/include/dbg.h
.
git clone https://github.com/sharkdp/dbg-macro sudo ln -s $(readlink -f dbg-macro/dbg.h) /usr/include/dbg.h
Ideally, if this turns out to be a good idea, we would ship packages for various distributions so you don't have to make untracked changes to your filesystem.
Configuration
- Set the
DBG_MACRO_DISABLE
flag to disable thedbg(…)
macro (i.e. to make it a no-op). - Set the
DBG_MACRO_NO_WARNING
flag to disable the "'dbg.h' header is included in your code base" warnings.
Customization
If you want dbg(…)
to work for your custom datatype, you can simply overload operator<<
for std::ostream&
:
std::ostream& operator<<(std::ostream& out, const user_defined_type& v) { out << "…"; return out; }
If you want to modify the type name that is printed by dbg(…)
, you can add a custom get_type_name
overload:
// Customization point for type information namespace dbg_macro { std::string get_type_name(type_tag<bool>) { return "truth value"; } }
Acknowledgement
This project is inspired by Rusts dbg!(…)
macro .
Recommend
About Joyk
Aggregate valuable and interesting links.
Joyk means Joy of geeK