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Note that POSIX ^® specifies that the time() function must return a value of type time_t, representing time in seconds since the Epoch. Thus, POSIX-conforming applications that aren't intended to be portable to other environments may safely perform arithmetic operations on time_t objects.

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int do_work(int seconds_to_work) {
  time_t start = time(NULL);
  time_t current = start;

  if (start == (time_t)(-1)) {
    /* Handle error */
  }
  while (difftime(current, start) < seconds_to_work) {
    current = time(NULL);
    if (current == (time_t)(-1)) {
       /* Handle error */
    }
    /* ... */
  }
  return 0;
}

Note that this loop may might still not exit , because the range of time_t may might not be able to represent two times seconds_to_work apart.

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Search for vulnerabilities resulting from the violation of this rule on the CERT website.

Related Guidelines

CERT C++ Secure Coding Standard: MSC05-CPP. Do not manipulate time_t typed values directly

ISO/IEC 9899:1999 Section 7.23, "Date and time <time.h>"

Bibliography

\[[Kettlewell 2002|AA. Bibliography#Kettlewell 02]\] Section 4.1, "time_t"
\[[ISO/IEC 9899:1999|AA. Bibliography#ISO/IEC 9899-1999]\] Section 7.23, "Date and time <time.h>"

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      49. Miscellaneous (MSC)      MSC06-C. Be aware of compiler optimization when dealing with sensitive data