C++ reference: cstdio: fgetpos

fgetpos
int fgetpos (FILE * stream , fpos_t * position);

stdio.h

cplusplus.com

Get position in a stream.
Gets the value of the position indicator of the given stream and stores it in the location pointed by position in a format that is only intended for use as a paremeter in further calls to fsetpos.
If you want to get the current position of a stream for any other use than as a parameter for fsetpos you should call to ftell function.

Parameters.

stream: pointer to an open file.
position: pointer to a fpos_t object where the position will be stored.
fpos_t is defined in stdio.h as long and it is only used with fgetpos and fsetpos functions.

Return Value.
0 value indicates success.
non-zero value indicates error.

Example.

/* fgetpos example */
#include <stdio.h>
main()
{
   FILE * pFile;
   char c;
   int n;
   fpos_t pos;

   pFile = fopen ("myfile.txt","r");
   if (pFile==NULL) perror ("Error opening file");
   else
   {
     c = fgetc (pFile);
     printf ("1st character is %c\n",c);
     fgetpos (pFile,&pos);
     for (n=0;n<3;n++)
     {
        fsetpos (pFile,&pos);
        c = fgetc (pFile);
        printf ("2nd character is %c\n",c);
     }
     fclose (pFile);
   }
   return 0;
}

Output:
1st character is A 2nd character is B 2nd character is B 2nd character is B This example opens myfile.txt. It reads the first character once and then it reads 3 times the same second character.

See also.
fsetpos, ftell, fseek