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 $CPPFLAGS ...
Long answer:
I know this question is older, but I have a small contribution to make. Best practice is always automatize what otherwise can became a source of error (or oblivion).
I was used to a function that created the version number for me. But I prefer this function to return a float. My version number can be printed by: printf("%13.6f\n", version()); which issues something like: 150710.150411 (being Year (2 digits) month day DOT hour minute seconds).
But, well, the question is yours. If you prefer "major.minor.date.time", it will have to be a string. (Trust me, double is better. If you insist in a major, you can still use double if you set the major and let the decimals to be date+time, like: major.datetime = 1.150710150411
Lets get to business. The example bellow will work if you compile as usual, forgetting to set it, or use -DVERSION to set the version directly from shell, but better of all, I recommend the third option: use a makefile.
Three forms of compiling and the results:
Using make:
beco> make program.x
gcc -Wall -Wextra -g -O0 -ansi -pedantic-errors -c -DVERSION="\"3.33.20150710.045829\"" program.c -o program.o
gcc program.o -o program.x
Running:
__DATE__: 'Jul 10 2015'
__TIME__: '04:58:29'
VERSION: '3.33.20150710.045829'
Using -DVERSION:
beco> gcc program.c -o program.x -Wall -Wextra -g -O0 -ansi -pedantic-errors -DVERSION=\"2.22.$(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> 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 <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
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, &dia, &ano);
50 sscanf(tempo, "%d:%d:%d", &hora, &min, &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<=9999 and MINOR<=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=$(date +"%g%m%d.%H%M%S")
Source code (double version):
#ifndef VERSION
#define VERSION version()
#endif
double version(void);
int main(void)
{
printf("VERSION%s: '%13.6f'\n", (FUNC_VERSION?"()":""), VERSION);
return 0;
}
double version(void)
{
const char data[]=__DATE__;
const char tempo[]=__TIME__;
const char nomes[] = "JanFebMarAprMayJunJulAugSepOctNovDec";
char omes[4];
int ano, mes, dia, hora, min, seg;
char sversion[]="130910.001339";
double fv;
if(strlen(data)!=11||strlen(tempo)!=8)
return -1.0;
sscanf(data, "%s %d %d", omes, &dia, &ano);
sscanf(tempo, "%d:%d:%d", &hora, &min, &seg);
mes=(strstr(nomes, omes)-nomes)/3+1;
sprintf(sversion,"%04d%02d%02d.%02d%02d%02d", ano, mes, dia, hora, min, seg);
fv=atof(sversion);
return fv;
}
Note: this double function is there only in case you forget to define macro VERSION. If you use a makefile or set an alias gcc gcc -DVERSION=$(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!
