findfirst, findnext ??

Hi im using djgpp and want to use the findfirst and findnext to see if a file exists. It is in dos.h but I dont know how the function works, could somebody please help: findfirst(const char*, ffblk *, int) - thats what the compiler says but what is ffblk?

Thanks

Code:

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#include <stdio.h>
#include <dir.h>
#include <string.h>

#define ALL_ATTS ( \
  FA_DIREC | \
  FA_ARCH )

void walker ( char *path ) {
  struct ffblk finder;
  unsigned int res;

  for ( res = findfirst ( "*.*", &finder, ALL_ATTS );
        res == 0;
        res = findnext( &finder ) ) {
    if ( strcmp(finder.ff_name, ".") == 0 ) continue;  // current dir
    if ( strcmp(finder.ff_name, "..") == 0 ) continue; // parent dir

    // if its a directory, examine it
    // else compare the filename with the one we're looking for
    if ( finder.ff_attrib & FA_DIREC ) {
      char newpath[MAXPATH];
      strcpy( newpath, path );
      strcat( newpath, "\\" );
      strcat( newpath, finder.ff_name);
      chdir( finder.ff_name );
      walker( newpath );
      chdir( ".." );
    } else {
      if ( strcmp( finder.ff_name, "words.txt" ) == 0 ) {
        printf( "Found!!!" );
      }
    }
  }
}

int main ( ) {
  char *root = "\\";
  chdir( root );
  walker( root );
  return 0;
}

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