How to use DATE and TIME predefined macros in as two integers then stringify

Question

Want to use    DATE    and    TIME    as integer for giving automated version to my code in compile time    define STRINGIZER arg       arg  define STR VALUE arg       STRINGIZER arg    define DATE as int str useD   DATE       What can be done    define TIME as int str useT   TIME       What can be done     define VERSION 1 4   define COMPLETE VERSION STR VALUE VERSION      DATE as int str     TIME as int str   and get COMPLETE VERSION as string in a const unsigned char      const unsigned char completeVersion        COMPLETE VERSION    Should output 1 4 1432 2234 something   One of the possible solution could be but did not work   convert-date-to-unsigned-int   In context of compile time  convertint-date-and-time-string-to-just-integers-in-c  One can refer  expanssion-and-stringification-how-to-get-the-marco-name-not-its-value

User · Answer

Short answer  asked version    format 3 33 20150710 182906   Please  simple use a makefile with   MAJOR   3 MINOR   33 BUILD     shell date    Y m d  H M S   VERSION        MAJOR    MINOR    BUILD     CPPFLAGS   -DVERSION   VERSION   program x   source c        gcc   CPPFLAGS  source c -o program x   and if you don t want a makefile  shorter yet  just compile with   gcc source c -o program x -DVERSION   2 22   date    Y m d  H M S         Short answer  suggested version    format 150710 182906   Use a double for version number   MakeFile   VERSION     shell date    g m d  H M S   CPPFLAGS   -DVERSION   VERSION  program x   source c       gcc   CPPFLAGS  source c -o program x   Or a simple bash command     gcc source c -o program x -DVERSION   date    g m d  H M S     Tip  Still don t like makefile or is it just for a not-so-small test program  Add this line    export CPPFLAGS  -DVERSION    date    g m d  H M S     to your    profile  and remember compile with gcc  CPPFLAGS        Long answer   I know this question is older  but I have a small contribution to make  Best practice is always automatize what otherwise can became a source of error  or oblivion    I was used to a function that created the version number for me  But I prefer this function to return a float  My version number can be printed by  printf   13 6f n   version     which issues something like  150710 150411  being Year  2 digits  month day DOT hour minute seconds    But  well  the question is yours  If you prefer  major minor date time   it will have to be a string   Trust me  double is better  If you insist in a major  you can still use double if you set the major and let the decimals to be date time  like  major datetime   1 150710150411  Lets get to business  The example bellow will work if you compile as usual  forgetting to set it  or use -DVERSION to set the version directly from shell  but better of all  I recommend the third option  use a makefile     Three forms of compiling and the results   Using make   beco gt  make program x gcc -Wall -Wextra -g -O0 -ansi -pedantic-errors -c -DVERSION    3 33 20150710 045829    program c -o program o gcc  program o -o program x   Running     DATE     Jul 10 2015    TIME     04 58 29  VERSION   3 33 20150710 045829    Using -DVERSION   beco gt  gcc program c -o program x -Wall -Wextra -g -O0 -ansi -pedantic-errors -DVERSION   2 22   date    Y m d  H M S       Running     DATE     Jul 10 2015    TIME     04 58 37  VERSION   2 22 20150710 045837    Using the build-in function   beco gt  gcc program c -o program x -Wall -Wextra -g -O0 -ansi -pedantic-errors   Running     DATE     Jul 10 2015    TIME     04 58 43  VERSION     1 11 20150710 045843      Source code    1  include  lt stdio h gt    2  include  lt stdlib h gt    3  include  lt string h gt    4    5  define FUNC VERSION  0    6  ifndef VERSION   7    define MAJOR 1   8    define MINOR 11   9    define VERSION version    10    undef FUNC VERSION  11    define FUNC VERSION  1   12   char sversion    9999 9999 20150710 045535    13  endif  14   15  if FUNC VERSION   16 char  version void    17  endif  18   19 int main void   20    21   22   printf    DATE      s  n     DATE      23   printf    TIME      s  n     TIME      24   25   printf  VERSION s    s  n    FUNC VERSION           VERSION    26   return 0   27    28   29    String format      30      DATE    Oct  8 2013      31       TIME    00 13 39      32  33    Version Function  returns the version string     34  if FUNC VERSION   35 char  version void   36    37   const char data     DATE     38   const char tempo     TIME     39   const char nomes      JanFebMarAprMayJunJulAugSepOctNovDec    40   char omes 4    41   int ano  mes  dia  hora  min  seg   42   43   if strcmp sversion  9999 9999 20150710 045535     44     return sversion   45   46   if strlen data   11  strlen tempo   8   47     return NULL   48   49   sscanf data    s  d  d   omes   amp dia   amp ano    50   sscanf tempo    d  d  d    amp hora   amp min   amp seg    51   mes  strstr nomes  omes -nomes  3 1   52   sprintf sversion   d  d  04d 02d 02d  02d 02d 02d   MAJOR  MINOR  ano  mes  dia  hora  min  seg    53   54   return sversion   55    56  endif     Please note that the string is limited by MAJOR lt  9999 and MINOR lt  9999  Of course  I set this high value that will hopefully never overflow  But using double is still better  plus  it s completely automatic  no need to set MAJOR and MINOR by hand    Now  the program above is a bit too much  Better is to remove the function completely  and guarantee that the macro VERSION is defined  either by -DVERSION directly into GCC command line  or an alias that automatically add it so you can t forget   or the recommended solution  to include this process into a makefile   Here it is the makefile I use     MakeFile source     1   MAJOR   3   2   MINOR   33   3   BUILD     shell date    Y m d  H M S     4   VERSION        MAJOR    MINOR    BUILD       5   CC   gcc   6   CFLAGS   -Wall -Wextra -g -O0 -ansi -pedantic-errors   7   CPPFLAGS   -DVERSION   VERSION    8   LDLIBS     9     10      x     c  11            CC    CFLAGS    CPPFLAGS    LDLIBS     -o        A better version with DOUBLE  Now that I presented you  your  preferred solution  here it is my solution   Compile with  a  makefile or  b  gcc directly    a  MakeFile      VERSION     shell date    g m d  H M S      CC   gcc    CFLAGS   -Wall -Wextra -g -O0 -ansi -pedantic-errors     CPPFLAGS   -DVERSION   VERSION     LDLIBS        x     c            CC    CFLAGS    CPPFLAGS    LDLIBS     -o       b  Or a simple bash command      gcc program c -o program x -Wall -Wextra -g -O0 -ansi -pedantic-errors -DVERSION   date    g m d  H M S       Source code  double version     ifndef VERSION    define VERSION version    endif  double version void    int main void      printf  VERSION s    13 6f  n    FUNC VERSION           VERSION     return 0     double version void      const char data     DATE      const char tempo     TIME      const char nomes      JanFebMarAprMayJunJulAugSepOctNovDec     char omes 4     int ano  mes  dia  hora  min  seg    char sversion    130910 001339     double fv     if strlen data   11  strlen tempo   8      return -1 0     sscanf data    s  d  d   omes   amp dia   amp ano     sscanf tempo    d  d  d    amp hora   amp min   amp seg     mes  strstr nomes  omes -nomes  3 1    sprintf sversion   04d 02d 02d  02d 02d 02d   ano  mes  dia  hora  min  seg     fv atof sversion      return fv      Note  this double function is there only in case you forget to define macro VERSION  If you use a makefile or set an alias gcc gcc -DVERSION   date    g m d  H M S    you can safely delete this function completely     Well  that s it  A very neat and easy way to setup your version control and never worry about it again

User · Answer

If you can use a C   compiler to build the object file that you want to contain your version string  then we can do exactly what you want   The only magic here is that C   allows you to use expressions to statically initialize an array  while C doesn t   The expressions need to be fully computable at compile time  but these expressions are  so it s no problem   We build up the version string one byte at a time  and get exactly what we want      source file version num h   ifndef VERSION NUM H   define VERSION NUM H    define VERSION MAJOR 1  define VERSION MINOR 4    endif    VERSION NUM H        source file build defs h   ifndef BUILD DEFS H   define BUILD DEFS H      Example of   DATE   string   Jul 27 2012                                  01234567890   define BUILD YEAR CH0    DATE    7    define BUILD YEAR CH1    DATE    8    define BUILD YEAR CH2    DATE    9    define BUILD YEAR CH3    DATE   10      define BUILD MONTH IS JAN    DATE   0      J   amp  amp    DATE   1      a   amp  amp    DATE   2      n    define BUILD MONTH IS FEB    DATE   0      F    define BUILD MONTH IS MAR    DATE   0      M   amp  amp    DATE   1      a   amp  amp    DATE   2      r    define BUILD MONTH IS APR    DATE   0      A   amp  amp    DATE   1      p    define BUILD MONTH IS MAY    DATE   0      M   amp  amp    DATE   1      a   amp  amp    DATE   2      y    define BUILD MONTH IS JUN    DATE   0      J   amp  amp    DATE   1      u   amp  amp    DATE   2      n    define BUILD MONTH IS JUL    DATE   0      J   amp  amp    DATE   1      u   amp  amp    DATE   2      l    define BUILD MONTH IS AUG    DATE   0      A   amp  amp    DATE   1      u    define BUILD MONTH IS SEP    DATE   0      S    define BUILD MONTH IS OCT    DATE   0      O    define BUILD MONTH IS NOV    DATE   0      N    define BUILD MONTH IS DEC    DATE   0      D      define BUILD MONTH CH0         BUILD MONTH IS OCT    BUILD MONTH IS NOV    BUILD MONTH IS DEC     1     0     define BUILD MONTH CH1                    BUILD MONTH IS JAN     1               BUILD MONTH IS FEB     2               BUILD MONTH IS MAR     3               BUILD MONTH IS APR     4               BUILD MONTH IS MAY     5               BUILD MONTH IS JUN     6               BUILD MONTH IS JUL     7               BUILD MONTH IS AUG     8               BUILD MONTH IS SEP     9               BUILD MONTH IS OCT     0               BUILD MONTH IS NOV     1               BUILD MONTH IS DEC     2                 error default                     define BUILD DAY CH0     DATE   4   gt    0        DATE   4      0    define BUILD DAY CH1    DATE    5         Example of   TIME   string   21 06 19                                  01234567   define BUILD HOUR CH0    TIME   0    define BUILD HOUR CH1    TIME   1     define BUILD MIN CH0    TIME   3    define BUILD MIN CH1    TIME   4     define BUILD SEC CH0    TIME   6    define BUILD SEC CH1    TIME   7      if VERSION MAJOR  gt  100   define VERSION MAJOR INIT         VERSION MAJOR   100     0             VERSION MAJOR   100    10     0            VERSION MAJOR   10     0     elif VERSION MAJOR  gt  10   define VERSION MAJOR INIT         VERSION MAJOR   10     0            VERSION MAJOR   10     0     else   define VERSION MAJOR INIT        VERSION MAJOR    0     endif   if VERSION MINOR  gt  100   define VERSION MINOR INIT         VERSION MINOR   100     0             VERSION MINOR   100    10     0            VERSION MINOR   10     0     elif VERSION MINOR  gt  10   define VERSION MINOR INIT         VERSION MINOR   10     0            VERSION MINOR   10     0     else   define VERSION MINOR INIT        VERSION MINOR    0     endif     endif    BUILD DEFS H        source file main c   include  version num h   include  build defs h      want something like  1 4 1432 2234  const unsigned char completeVersion           VERSION MAJOR INIT               VERSION MINOR INIT       -    V    -       BUILD YEAR CH0  BUILD YEAR CH1  BUILD YEAR CH2  BUILD YEAR CH3       -       BUILD MONTH CH0  BUILD MONTH CH1       -       BUILD DAY CH0  BUILD DAY CH1       T       BUILD HOUR CH0  BUILD HOUR CH1               BUILD MIN CH0  BUILD MIN CH1               BUILD SEC CH0  BUILD SEC CH1        0        include  lt stdio h gt   int main int argc  char   argv        printf   s n   completeVersion          prints something similar to  1 4-V-2013-05-09T15 34 49     This isn t exactly the format you asked for  but I still don t fully understand how you want days and hours mapped to an integer   I think it s pretty clear how to make this produce any desired string

User · Answer

I have a partial answer for you   This is based on what I get from GCC     DATE   gives something like  Jul 27 2012     TIME   gives something like 21 06 19  Put this text in an include file called build defs h    ifndef BUILD DEFS H   define BUILD DEFS H    define BUILD YEAR     DATE   7  -  0     1000       DATE   8  -  0     100      DATE   9  -  0     10     DATE   10  -  0     define BUILD DATE     DATE   4  -  0     10     DATE   5  -  0      if 0  if    DATE   0      J   amp  amp    DATE   1      a   amp  amp    DATE   2      n        define BUILD MONTH  1  elif    DATE   0      F   amp  amp    DATE   1      e   amp  amp    DATE   2      b        define BUILD MONTH  2  elif    DATE   0      M   amp  amp    DATE   1      a   amp  amp    DATE   2      r        define BUILD MONTH  3  elif    DATE   0      A   amp  amp    DATE   1      p   amp  amp    DATE   2      r        define BUILD MONTH  4  elif    DATE   0      M   amp  amp    DATE   1      a   amp  amp    DATE   2      y        define BUILD MONTH  5  elif    DATE   0      J   amp  amp    DATE   1      u   amp  amp    DATE   2      n        define BUILD MONTH  6  elif    DATE   0      J   amp  amp    DATE   1      u   amp  amp    DATE   2      l        define BUILD MONTH  7  elif    DATE   0      A   amp  amp    DATE   1      u   amp  amp    DATE   2      g        define BUILD MONTH  8  elif    DATE   0      S   amp  amp    DATE   1      e   amp  amp    DATE   2      p        define BUILD MONTH  9  elif    DATE   0      O   amp  amp    DATE   1      c   amp  amp    DATE   2      t        define BUILD MONTH 10  elif    DATE   0      N   amp  amp    DATE   1      o   amp  amp    DATE   2      v        define BUILD MONTH 11  elif    DATE   0      D   amp  amp    DATE   1      e   amp  amp    DATE   2      c        define BUILD MONTH 12  else      error  Could not figure out month   endif  endif   define BUILD HOUR     TIME   0  -  0     10     TIME   1  -  0    define BUILD MIN     TIME   3  -  0     10     TIME   4  -  0    define BUILD SEC     TIME   6  -  0     10     TIME   7  -  0     endif    BUILD DEFS H   I tested the above with GCC on Linux   It all works great  except for the problem that I can t figure out how to get a number for the month   If you check the section that is under  if 0 you will see my attempt to figure out the month   GCC complains with this message   error  token   Jul 27 2012   is not valid in preprocessor expressions   It would be trivial to convert the three-letter month abbreviation into some sort of unique number  just subtract  A  from the first letter and  a  from the second and the third  and then convert to a base-26 number or something   But I want to make it evaluate to 1 for January and so on  and I can t figure out how to do that   EDIT  I just realized that you asked for strings  not expressions that evaluate to integer values   I tried to use these tricks to build a static string    define BUILD MAJOR 1  define BUILD MINOR 4  define VERSION STRINGIZE BUILD MAJOR      STRINGIZE BUILD MINOR   char build str           BUILD MAJOR    0       BUILD MINOR    0              DATE   7     DATE   8     DATE   9     DATE   10         0       GCC complains that  initializer element is not constant  for   DATE     Sorry  I m not sure how to help you   Maybe you can try this stuff with your compiler   Or maybe it will give you an idea   Good luck   P S  If you don t need things to be numbers  and you just want a unique build string  it s easy   const char  build str    Version    VERSION       DATE         TIME      With GCC  this results in something like   Version  1 4 Jul 27 2012 21 53 59

User · Answer

You could always write a simple program in Python or something to create an include file that has simple #define statements with a build number, time, and date. You would then need to run this program before doing a build.

If you like I'll write one and post source here.

If you are lucky, your build tool (IDE or whatever) might have the ability to run an external command, and then you could have the external tool rewrite the include file automatically with each build.

EDIT: Here's a Python program. This writes a file called build_num.h and has an integer build number that starts at 1 and increments each time this program is run; it also writes #define values for the year, month, date, hours, minutes and seconds of the time this program is run. It also has a #define for major and minor parts of the version number, plus the full VERSION and COMPLETE_VERSION that you wanted. (I wasn't sure what you wanted for the date and time numbers, so I went for just concatenated digits from the date and time. You can change this easily.)

Each time you run it, it reads in the build_num.h file, and parses it for the build number; if the build_num.h file does not exist, it starts the build number at 1. Likewise it parses out major and minor version numbers, and if the file does not exist defaults those to version 0.1.

import time

FNAME = "build_num.h"

build_num = None
version_major = None
version_minor = None

DEF_BUILD_NUM = "#define BUILD_NUM "
DEF_VERSION_MAJOR = "#define VERSION_MAJOR "
DEF_VERSION_MINOR = "#define VERSION_MINOR "

def get_int(s_marker, line):
    _, _, s = line.partition(s_marker) # we want the part after the marker
    return int(s)

try:
    with open(FNAME) as f:
        for line in f:
            if DEF_BUILD_NUM in line:
                build_num = get_int(DEF_BUILD_NUM, line)
                build_num += 1
            elif DEF_VERSION_MAJOR in line:
                version_major = get_int(DEF_VERSION_MAJOR, line)
            elif DEF_VERSION_MINOR in line:
                version_minor = get_int(DEF_VERSION_MINOR, line)
except IOError:
    build_num = 1
    version_major = 0
    version_minor = 1

assert None not in (build_num, version_major, version_minor)


with open(FNAME, 'w') as f:
    f.write("#ifndef BUILD_NUM_H\n")
    f.write("#define BUILD_NUM_H\n")
    f.write("\n")
    f.write(DEF_BUILD_NUM + "%d\n" % build_num)
    f.write("\n")
    t = time.localtime()
    f.write("#define BUILD_YEAR %d\n" % t.tm_year)
    f.write("#define BUILD_MONTH %d\n" % t.tm_mon)
    f.write("#define BUILD_DATE %d\n" % t.tm_mday)
    f.write("#define BUILD_HOUR %d\n" % t.tm_hour)
    f.write("#define BUILD_MIN %d\n" % t.tm_min)
    f.write("#define BUILD_SEC %d\n" % t.tm_sec)
    f.write("\n")
    f.write("#define VERSION_MAJOR %d\n" % version_major)
    f.write("#define VERSION_MINOR %d\n" % version_minor)
    f.write("\n")
    f.write("#define VERSION \"%d.%d\"\n" % (version_major, version_minor))
    s = "%d.%d.%04d%02d%02d.%02d%02d%02d" % (version_major, version_minor,
            t.tm_year, t.tm_mon, t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec)
    f.write("#define COMPLETE_VERSION \"%s\"\n" % s)
    f.write("\n")
    f.write("#endif // BUILD_NUM_H\n")

I made all the defines just be integers, but since they are simple integers you can use the standard stringizing tricks to build a string out of them if you like. Also you can trivially extend it to build additional pre-defined strings.

This program should run fine under Python 2.6 or later, including any Python 3.x version. You could run it under an old Python with a few changes, like not using .partition() to parse the string.

User · Answer

For anyone just looking to replace the extra ' ' (space) if day is less than 10 then use:

#define BUILD_DATE (char const[]) { __DATE__[0], __DATE__[1], __DATE__[2], __DATE__[3], (__DATE__[4] == ' ' ?  '0' : __DATE__[4]), __DATE__[5], __DATE__[6], __DATE__[7], __DATE__[8], __DATE__[9], __DATE__[10], __DATE__[11] }

Output: Sep 06 2019

User · Answer

Here is a working version of the  build defs    This is similar to my previous answer but I figured out the build month    You just can t compute build month in a  if statement  but you can use a ternary expression that will be compiled down to a constant    Also  according to the documentation  if the compiler cannot get the time of day it will give you question marks for these strings   So I added tests for this case  and made the various macros return an obviously wrong value  99  if this happens    ifndef BUILD DEFS H   define BUILD DEFS H      Example of   DATE   string   Jul 27 2012     Example of   TIME   string   21 06 19    define COMPUTE BUILD YEAR                      DATE    7  -  0     1000                DATE    8  -  0      100                DATE    9  -  0       10                DATE   10  -  0              define COMPUTE BUILD DAY                       DATE   4   gt    0        DATE   4  -  0     10   0                 DATE   5  -  0              define BUILD MONTH IS JAN    DATE   0      J   amp  amp    DATE   1      a   amp  amp    DATE   2      n    define BUILD MONTH IS FEB    DATE   0      F    define BUILD MONTH IS MAR    DATE   0      M   amp  amp    DATE   1      a   amp  amp    DATE   2      r    define BUILD MONTH IS APR    DATE   0      A   amp  amp    DATE   1      p    define BUILD MONTH IS MAY    DATE   0      M   amp  amp    DATE   1      a   amp  amp    DATE   2      y    define BUILD MONTH IS JUN    DATE   0      J   amp  amp    DATE   1      u   amp  amp    DATE   2      n    define BUILD MONTH IS JUL    DATE   0      J   amp  amp    DATE   1      u   amp  amp    DATE   2      l    define BUILD MONTH IS AUG    DATE   0      A   amp  amp    DATE   1      u    define BUILD MONTH IS SEP    DATE   0      S    define BUILD MONTH IS OCT    DATE   0      O    define BUILD MONTH IS NOV    DATE   0      N    define BUILD MONTH IS DEC    DATE   0      D      define COMPUTE BUILD MONTH                    BUILD MONTH IS JAN     1              BUILD MONTH IS FEB     2              BUILD MONTH IS MAR     3              BUILD MONTH IS APR     4              BUILD MONTH IS MAY     5              BUILD MONTH IS JUN     6              BUILD MONTH IS JUL     7              BUILD MONTH IS AUG     8              BUILD MONTH IS SEP     9              BUILD MONTH IS OCT    10              BUILD MONTH IS NOV    11              BUILD MONTH IS DEC    12                error default     99           define COMPUTE BUILD HOUR     TIME   0  -  0     10     TIME   1  -  0    define COMPUTE BUILD MIN      TIME   3  -  0     10     TIME   4  -  0    define COMPUTE BUILD SEC      TIME   6  -  0     10     TIME   7  -  0      define BUILD DATE IS BAD    DATE   0            define BUILD YEAR    BUILD DATE IS BAD    99   COMPUTE BUILD YEAR   define BUILD MONTH   BUILD DATE IS BAD    99   COMPUTE BUILD MONTH   define BUILD DAY     BUILD DATE IS BAD    99   COMPUTE BUILD DAY    define BUILD TIME IS BAD    TIME   0            define BUILD HOUR    BUILD TIME IS BAD    99    COMPUTE BUILD HOUR   define BUILD MIN     BUILD TIME IS BAD    99    COMPUTE BUILD MIN   define BUILD SEC     BUILD TIME IS BAD    99    COMPUTE BUILD SEC     endif    BUILD DEFS H   With the following test code  the above works great   printf   04d- 02d- 02dT 02d  02d  02d n   BUILD YEAR  BUILD MONTH  BUILD DAY  BUILD HOUR  BUILD MIN  BUILD SEC     However  when I try to use those macros with your stringizing macro  it stringizes the literal expression   I don t know of any way to get the compiler to reduce the expression to a literal integer value and then stringize   Also  if you try to statically initialize an array of values using these macros  the compiler complains  with an error  initializer element is not constant message   So you cannot do what you want with these macros   At this point I m thinking that your best bet is the Python script that just generates a new include file for you   You can pre-compute anything you want in any format you want   If you don t want Python we can write an AWK script or even a C program

User · Answer

it is very simple       in make file        1                      OBJS          version o  lt  lt    add to your obj lists        2                      DATE     shell date   char szVersionStr 20      Y- m- d  H  M  S      lt  lt    add   all version   ProgramID    lt  lt    version add at first  version                    lt  lt    add  echo    DATE    gt  version c   lt    add   create version c file     in program        3                extern char szVersionStr 20      using        4       printf   Version   s n   szVersionStr

[c] How to use DATE and TIME predefined macros in as two integers, then stringify?

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[c] How to use __DATE__ and __TIME__ predefined macros in as two integers, then stringify?