How to output Pointer

[dai-2584]

int nP = 3;
SPDLOG_LOGGER_INFO(g_pLogger, "&nP={}", &nP);

core.h:902:5: error: static assertion failed: formatting of non-void pointers is disallowed
static_assert(!sizeof(T), "formatting of non-void pointers is disallowed");

How to output a Pointer?

[tt4g]

spdlog use fmt library to format argument at runtime.
You can use fmt::ptr():

int nP = 3;
SPDLOG_LOGGER_INFO(g_pLogger, "&nP={}", fmt::ptr(&nP));

[dai-2584]

OK , thank you!

[caibf]

Code:

HWND hwnd_child = viewer->GetWindowId();
KL_LOGGER_DEBUG("Create the visualizer viewer({}).", fmt::ptr(hwnd_child));

Output:
Create the visualizer viewer(0x1.2003275e-317).

@tt4g Why the result isn't the pointer address?

[tt4g]

@caibf Set pointer syntax p.
https://fmt.dev/8.0.0/syntax.html

 HWND hwnd_child = viewer->GetWindowId();
- KL_LOGGER_DEBUG("Create the visualizer viewer({}).", fmt::ptr(hwnd_child));
+ KL_LOGGER_DEBUG("Create the visualizer viewer({:p}).", fmt::ptr(hwnd_child));

And it is recommended that this question be asked in the fmt repository.

[caibf]

I have tried this, still the same result. Maybe the fmt version(I use spdlog 1.5.0, depends on fmt 6.1.2) problem.

But make a simple demo, result it's ok.

double elapsed_time = 0;
HWND hwnd_child = (HWND)&elapsed_time;
KL_LOGGER_DEBUG("Create the visualizer viewer({}).", fmt::ptr(hwnd_child));
KL_LOGGER_DEBUG("Create the visualizer viewer({:p}).", fmt::ptr(hwnd_child));

Output:
Create the visualizer viewer(0xef372ff6e8).
Create the visualizer viewer(0xef372ff6e8).

And it is recommended that this question be asked in the fmt repository.

OK. I will move this question to its repository.