On 01/29/2017 06:22 PM, Andrew Makhorin wrote: > Hi Chris, > >>> Not sure, but gmtime_s looks like a MSVC function. Could you point me >>> out where gmtime_s is standardized? Thanks. >> >> gmtime_s is included in the (optional) annex K of C11. However, the >> parameters are reversed compared to the MSVC version and the standard >> one returns struct tm * while the MSVC one returns errno_t. >> >> Moreover, some searching shows that gmtime_s is documented starting >> with VS 2010 (and _gmtime_s in VS 2005 and VS 2008). However, since VS >> 2005 gmtime returns a different pointer per thread [1], so there is no >> reason to use gmtime_s here - gmtime_s offers additional error >> checking for null pointers, which is not an issue in this code. >> > > Thank you for information. > > As Heinrich noticed, gmtime, strerror, and strtok are non-thread-safe > (for example, in most recent version of glibc strtok just uses a static > pointer without a tls specifier), so in a multi-threaded environment > thread-safe versions of these functions should be used. The problem I > encountered is that gcc (Debian 4.7.2-5) 4.7.2 installed on my Linux > machine doesn't have gmtime_s, strerror_s, and strtok_s. It is unclear > what to do if no thread-safe version of these functions are available. >
glibc (and POSIX 2008) has these functions: struct tm *gmtime_r(const time_t *timep, struct tm *result); int strerror_r(int errnum, char *buf, size_t buflen); char *strtok_r(char *str, const char *delim, char **saveptr); Windows (and C11) supply errno_t gmtime_s(struct tm* _tm, const __time_t* time); errno_t strerror_s(char *buffer, size_t numberOfElements, int errnum); char *strtok_s(char *strToken, const char *strDelimit, char **context); We can use __WOE__ to decide which function to use. Best regards Heinrich Schuchardt _______________________________________________ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk
