Question

I am working with batches of files that contain information about the same object at the different times of its life, and the only way to order them is by creation date.
I was using this:

//char* buffer has the name of file
struct stat buf;
FILE *tf;
tf = fopen(buffer,"r");
//check handle
fstat(tf, &buf);
fclose(tf);
pMyObj->lastchanged=buf.st_mtime;

But that does not seems to work.
What am I doing wrong? Are there other, more reliable/simple ways to get file creation date under Linux?

Answer 1

fstat works on file descriptors, not FILE structures. The simplest version:

#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>

#ifdef HAVE_ST_BIRTHTIME
#define birthtime(x) x.st_birthtime
#else
#define birthtime(x) x.st_ctime
#endif

int main(int argc, char *argv[])
{
        struct stat st;
        size_t i;

        for( i=1; i<argc; i++ )
        {
                if( stat(argv[i], &st) != 0 )
                        perror(argv[i]);
                printf("%i\n", birthtime(st));
        }

        return 0;
}

You will need to figure out if your system has st_birthtime in its stat structure by inspecting sys/stat.h or using some kind of autoconf construct.