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4.11 _getenv_init()
Defined in rt_misc.h, the _getenv_init() function enables a user version of getenv() to initialize itself.
This function is not part of the C library standard, but the ARM® C library supports it as an extension.
Syntax
void_getenv_init(void);
Usage
If this function is defined, the C library initialization
code calls it when the library is initialized, that is, before main() is
entered.