How to print time in format 2009-08-10 18 17 54 811

Question

What s the best method to print out time in C in the format 2009-08-10  18 17 54 811

User · Accepted Answer

Use strftime      include  lt stdio h gt   include  lt time h gt   int main         time t timer      char buffer 26       struct tm  tm info       timer   time NULL       tm info   localtime  amp timer        strftime buffer  26    Y- m- d  H  M  S   tm info       puts buffer        return 0      For milliseconds part  have a look at this question  How to measure time in milliseconds using ANSI C

User · Answer

You could use strftime  but struct tm doesn t have resolution for parts of seconds  I m not sure if that s absolutely required for your purposes   struct tm tm     Set tm to the correct time    char s 20      strlen  2009-08-10 18 17 54     1    strftime s  20    F  H  M  S    amp tm

User · Answer

time h defines a strftime function which can give you a textual representation of a time t using something like    include  lt stdio h gt   include  lt time h gt  int main  void        char buff 100       time t now   time  0       strftime  buff  100    Y- m- d  H  M  S 000   localtime   amp now        printf    s n   buff       return 0      but that won t give you sub-second resolution since that s not available from a time t  It outputs   2010-09-09 10 08 34 000   If you re really constrained by the specs and do not want the space between the day and hour  just remove it from the format string

User · Answer

None of the solutions on this page worked for me  I mixed them up and made them working with Windows and Visual Studio 2019  Here s How    include  lt Windows h gt   include  lt time h gt    include  lt chrono gt   static int gettimeofday struct timeval  tp  struct timezone  tzp        namespace sc   std  chrono      sc  system clock  duration d   sc  system clock  now   time since epoch        sc  seconds s   sc  duration cast lt sc  seconds gt  d       tp- gt tv sec   s count        tp- gt tv usec   sc  duration cast lt sc  microseconds gt  d - s  count        return 0     static char  getFormattedTime         static char buffer 26           For Miliseconds     int millisec      struct tm  tm info      struct timeval tv          For Time     time t rawtime      struct tm  timeinfo       gettimeofday  amp tv  NULL        millisec   lrint tv tv usec   1000 0       if  millisec  gt   1000                 millisec -  1000          tv tv sec               time  amp rawtime       timeinfo   localtime  amp rawtime        strftime buffer  26   quot  Y  m  d  H  M  S quot   timeinfo       sprintf s buffer  26   quot  s  03d quot   buffer  millisec        return buffer      Result    2020 08 02 06 41 59 107   2020 08 02 06 41 59 196

User · Answer

Following code prints with microsecond precision  All we have to do is use gettimeofday and strftime on tv sec and append tv usec to the constructed string    include  lt stdio h gt   include  lt time h gt   include  lt sys time h gt  int main void        struct timeval tmnow      struct tm  tm      char buf 30   usec buf 6       gettimeofday  amp tmnow  NULL       tm   localtime  amp tmnow tv sec       strftime buf 30   Y  m  dT H  M  S   tm       strcat buf           sprintf usec buf   dZ   int tmnow tv usec       strcat buf usec buf       printf   s  buf       return 0

User · Answer

The above answers do not fully answer the question  specifically the millisec part   My solution to this is to use gettimeofday before strftime  Note the care to avoid rounding millisec to  1000   This is based on Hamid Nazari s answer    include  lt stdio h gt   include  lt sys time h gt   include  lt time h gt   include  lt math h gt   int main       char buffer 26     int millisec    struct tm  tm info    struct timeval tv     gettimeofday  amp tv  NULL      millisec   lrint tv tv usec 1000 0      Round to nearest millisec   if  millisec gt  1000       Allow for rounding up to nearest second     millisec - 1000      tv tv sec           tm info   localtime  amp tv tv sec      strftime buffer  26    Y  m  d  H  M  S   tm info     printf   s  03d n   buffer  millisec      return 0

User · Answer

trick       int time len   0  n      struct tm  tm info      struct timeval tv       gettimeofday  amp tv  NULL       tm info   localtime  amp tv tv sec       time len  strftime log buff  sizeof log buff    y m d  H  M  S   tm info       time len  snprintf log buff time len sizeof log buff-time len    03ld   tv tv usec 1000

[c] How to print time in format: 2009-08-10 18:17:54.811

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