Determines file-access permission.
| #include <io.h> | Required only for function declarations | |
| #include <errno.h> | Required for definition of errno constants |
int _access( char *pathname, int mode );
| pathname | File or directory path name | |
| mode | Permission setting |
With files, the _access function determines whether the specified file exists and can be accessed in mode. The possible mode values and their meanings in the _access call are as follows:
| Value | Meaning |
| 00 | Check for existence only |
| 02 | Check for write permission |
| 04 | Check for read permission |
| 06 | Check for read and write permission |
With directories, _access determines only whether the specified directory exists; in DOS, all directories have read and write access.
The _access function returns the value 0 if the file has the given mode. A return value of –1 indicates that the named file does not exist or is not accessible in the given mode, and errno is set to one of the following values:
| Value | Meaning |
| EACCES | Access denied: the file's permission setting does not allow the specified access. |
| ENOENT | File or path name not found. |
Standards:UNIX
16-Bit:DOS, QWIN, WIN, WIN DLL
32-Bit:DOS32X
Use _access for compatibility with ANSI naming conventions of non-ANSI functions. Use access and link with OLDNAMES.LIB for UNIX compatibility.
/* ACCESS.C: This example uses _access to check the file named "data"
* 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 exists\n" );
/* Check for write permission */
if( (_access( "access.c", 2 )) != -1 )
printf( "File has write permission\n" );
}
}
File exists
File has write permission