https://github.com/lebaoworks/cpp-tips
Defer like Go, format like C printf and other stuff...
https://github.com/lebaoworks/cpp-tips
cpp cpp11 defer formatting tips tricks
Last synced: 5 months ago
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Defer like Go, format like C printf and other stuff...
- Host: GitHub
- URL: https://github.com/lebaoworks/cpp-tips
- Owner: lebaoworks
- License: mit
- Created: 2024-04-06T18:25:38.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-03-09T12:45:33.000Z (over 1 year ago)
- Last Synced: 2025-10-22T22:38:37.123Z (9 months ago)
- Topics: cpp, cpp11, defer, formatting, tips, tricks
- Language: C++
- Homepage:
- Size: 153 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# cpp-tips
## Introduction
This is the collection of snippets I found on internet or made by me.
## Contents:
- [Defer function](#defer)
- [Format like printf](#format-like-printf)
- [Runtime exception with format](#runtime-exception-with-format)
## Defer
- Requirement: C++11 or later.
- Source: [pmttavaras's answer](https://stackoverflow.com/a/42060129) on stackoverflow.
- Modified to use move-semantic for true zero-overhead by me.
Deferred functions will be called at the end of the scope where they were declared, in last-in-first-out order.
Snippet:
```cpp
#include
struct defer_dummy {};
template
struct deferer
{
F _f;
deferer(F&& f) noexcept : _f(f) {}
~deferer() { _f(); }
};
template
inline deferer operator*(defer_dummy, F&& f) noexcept { return deferer(std::move(f)); }
#define DEFER_(LINE) zz_defer##LINE
#define DEFER(LINE) DEFER_(LINE)
#define defer auto DEFER(__LINE__) = defer_dummy{} *[&]()
```
Sample:
```cpp
int main()
{
defer{ printf("4\n"); };
defer{ printf("3\n"); };
{
defer{ printf("1\n"); };
}
defer{ printf("2\n"); };
}
```
## Format like printf
- Source: [ifreilicht's answer](https://stackoverflow.com/a/26221725) on stackoverflow.
- Modified to be more efficient by me.
Snippet:
```cpp
#include
#include
#include
#include
namespace nstd
{
template
std::string format(const std::string& format, const Args&... args)
{
int size_s = std::snprintf(nullptr, 0, format.c_str(), args...);
if (size_s < 0) throw std::runtime_error("Error during formatting");
std::string ret(size_s, '\x00');
std::snprintf(&ret[0], size_s + 1, format.c_str(), args...);
return ret;
}
}
```
Sample:
```cpp
int main()
{
std::cout << nstd::format("hello %s!\n", "lebaoworks");
}
```
## Runtime exception with format
- Source: Me.
- Requirement: [format](#format-like-printf)
Snippet:
```cpp
#include
#include
namespace nstd
{
struct runtime_error : public std::runtime_error
{
template
runtime_error(const std::string& format, const Args&... args) :
std::runtime_error(nstd::format(format, args...)) {}
};
}
```
Sample:
```cpp
int main()
{
try
{
throw nstd::runtime_error("test except by %s", "lebaoworks");
}
catch (std::exception& e)
{
printf("Got exception: %s", e.what());
}
}
```