MSDN 對於_access()函式的介紹：

int _access( const char *path, int mode );  Required header：<io.h>，Optional headers：<errno.h>

Return Value

Each of these functions returns 0 if the file has the given mode. The function returns –1 if the named file does not exist or is not accessible in the given mode; in this case, errno

EACCES

Access denied: file’s permission setting does not allow specified access.

ENOENT

Filename or path not found.

Parameters

path

File or directory path

mode

Permission setting

Remarks

When used with files, the _access function determines whether the specified file exists and can be accessed as specified by the value of mode

mode Value            Checks File For 
00                              Existence only 
02                              Write permission 
04                              Read permission 
06                              Read and write permission

/* ACCESS.C: This example uses _access to check the
 * file named "ACCESS.C" to see if it exists and if
 * writing is allowed.
 */

#include  <io.h>
#include  <stdio.h>
#include  <stdlib.h>

void main( void )
{
   /* Check for existence */
   if( (_access( "ACCESS.C", 0 )) != -1 )
   {
      printf( "File ACCESS.C exists " );
      /* Check for write permission */
      if( (_access( "ACCESS.C", 2 )) != -1 )
         printf( "File ACCESS.C has write permission " );
   }
}

Creates a new directory.

int _mkdir(  const char *dirname );

Each of these functions returns the value 0 if the new directory was created. On an error, the function returns –1 and sets errno as follows

// crt_makedir.c

#include <direct.h>
#include <stdlib.h>
#include <stdio.h>

int main( void )
{
   if( _mkdir( "\\testtmp" ) == 0 )
   {
      printf( "Directory '\\testtmp' was successfully created\n" );
      system( "dir \\testtmp" );
      if( _rmdir( "\\testtmp" ) == 0 )
        printf( "Directory '\\testtmp' was successfully removed\n"  );
      else
         printf( "Problem removing directory '\\testtmp'\n" );
   }
   else
      printf( "Problem creating directory '\\testtmp'\n" );
}