17 Language support library [support]

17.13 Other runtime support [support.runtime]

17.13.1 General [support.runtime.general]

1
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Headers <csetjmp> (nonlocal jumps), <csignal> (signal handling), <cstdarg> (variable arguments), and <cstdlib> (runtime environment getenv, system), provide further compatibility with C code.
2
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Calls to the function getenv ([cstdlib.syn]) shall not introduce a data race ([res.on.data.races]) provided that nothing modifies the environment.
[Note 1: 
Calls to the POSIX functions setenv and putenv modify the environment.
— end note]
3
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A call to the setlocale function may introduce a data race with other calls to the setlocale function or with calls to functions that are affected by the current C locale.
The implementation shall behave as if no library function other than locale​::​global calls the setlocale function.