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The rand function is not required to avoid data races.
SimilarlyAlso, the following library functions are also not required to avoid data races
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References
[N1401-C1X Draft Standard] Section 7.21.2.1 rand() function, Section 7.21.4.6 getenv() function, Section 7.22.5.8 strtok() function, Section 7.22.6.2 strerror() function, Section 7.25.3.1 asctime() function, Section 7.25.3.2 ctime() function
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