...will undefine it. This happens on macOS */
# ifdef __cplusplus
  int R_isnancpp(double); /* in mlutils...

...Reduced:

```
#ifdef __TINYC__
#elif defined(_WIN32)
#else
int atomic_load(const volatile int *p)
{
#ifdef...

...the C/C++ mistake with unreadable/unfollowable ``#ifdef`` everywhere

I try to structure my code...

...ATTR_SHIFT))

NCURSES_CAST is defined as:

#ifdef __cplusplus
extern "C" {
#define NCURSES_CAST(type...

...if !defined BR_INT128 && !defined BR_UMUL128
#ifdef __SIZEOF_INT128__
#define BR_INT128    1
#elif...

...realistic for ImportC. However, most .h files #ifdef out that stuff.

Hence:

https://github.com...

...ifdef GENERATOR_FILE
#error config.h is for the host, not build, machine.
#endif
#ifdef...

...ifdef GENERATOR_FILE
#error config.h is for the host, not build, machine.
#endif
#ifdef...

...is a version statement, resembling `{$ifdef}` in Pascal or `#ifdef` in C, but arguably cleaner...

...is also another `#ifdef` mess allowed in C:
```c
void func(
#ifdef FOO_INT_PARAM...