Q43144: C: Using the _dos_findfirst and _dosfindnext Functions

Article: Q43144
Product(s): See article
Version(s): 5.00 5.10 | 5.10
Operating System(s): MS_DOS | OS/2
Keyword(s): ENDUSER | s_quickc | mspl13_c
Last Modified: 17-MAY-1989

Question:

Why do all my files show up in addition to the subdirectories when
using the _dos_findfirst and _dos_findnext functions to find all the
subdirectories in my working directory?

Response:

When the attribute argument to the _dos_findfirst and _dos_findnext
functions is either _A_RDONLY, _A_HIDDEN, _A_SYSTEM, or _A_SUBDIR, the
functions will return all normal-attribute files.  A normal-attribute
file is any file that does not have a read-only, hidden, system, or
directory attribute.

Thus, the following function call will return either a normal file or
a subdirectory:

   _dos_findfirst( "*.*", _A_SUBDIR, &c_file )

To verify that the returned c_file is a subdirectory, check the
attribute field of the c_file to determine whether the _A_SUBDIR bit
is set. If so, then it is a subdirectory. This process may be
accomplished by bitwise-ANDing c_file.attrib with _A_SUBDIR and
checking for a nonzero result.

The following program illustrates the use of these functions:

#include <dos.h>
#include <stdio.h>

main()
{
        struct find_t c_file;

        _dos_findfirst( "*.*", _A_SUBDIR, &c_file );

        if( c_file.attrib & _A_SUBDIR )
        printf( "Directory listing %s\n", c_file.name );

        while (_dos_findnext(&c_file) == 0)
            if( c_file.attrib & _A_SUBDIR )
            printf( "Directory listing %s\n", c_file.name );
}