fstat - Information about Open File

Syntax

#include <sys\stat.h>
#include <sys\types.h>
int fstat(int handle, struct stat *buffer);

Description

fstat obtains information about the open file associated with the given handle and stores it in the structure to which buffer points. The <sys\stat.h> include file defines the stat structure. The stat structure contains the following fields:

Field

Value
st_mode
Bit mask for file mode information. fstat sets the S_IFCHR bit if handle refers to a device. The S_IFDIR bit is set if pathname specifies a directory. It sets the S_IFREG bit if handle refers to an ordinary file. It sets user read/write bits according to the permission mode of the file. The other bits have undefined values.


st_dev

Drive number of the disk containing the file.
st_rdev
Drive number of the disk containing the file (same as st_dev).
st_nlink
Always 1.
st_size
Size of the file in bytes.
st_atime
Time of last access of file.
st_mtime
Time of last modification of file.
st_ctime
Time of file creation.

There are three additional fields in the stat structure for portability to other operating systems; they have no meaning under the OS/2 operating system.

Note: If the given handle refers to a device, the size and time fields in the stat structure are not meaningful.

Returns

If it obtains the file status information, fstat returns 0. A return value of -1 indicates an error, and fstat sets errno to EBADF, showing an incorrect file handle.

Example Code

This example uses fstat to report the size of a file named data.

#include <time.h>#include <sys\types.h>
#include <sys\stat.h>
#include <stdio.h>

int main(void)
{
   struct stat buf;
   FILE *fp;
   int fh,result;
   char *buffer = "A line to output";

   fp = fopen("data", "w+");
   fprintf(fp, "%s", buffer);
   fflush(fp);
   fclose(fp);
   fp = fopen("data", "r");
   if (0 == fstat(fileno(fp), &buf)) {
      printf("file size is %ld\n", buf.st_size);
      printf("time modified is %s\n", ctime(&buf.st_atime));
   }
   else
      printf("Bad file handle\n");
   fclose(fp);
   return 0;

   /****************************************************************************
      The output should be similar to:

      file size is 16
      time modified is Thu May 16 16:08:14 1995
   ****************************************************************************/
}

Related Information

• stat

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