access

Syntax

#include <unistd.h> int access(const char *filename, int flags);

Description

This function determines what kind of access modes a given file allows. The parameter flags is the logical or of one or more of the following flags:

R_OK

Request if the file is readable. Since all files are readable under MS-DOS, this access mode always exists.

W_OK

Request if the file is writable.

X_OK

Request if the file is executable.

F_OK

Request if the file exists.

D_OK

Request if the file is really a directory.

Return Value

Zero if the requested access mode is allowed, nonzero if not.

Portability

ANSI/ISO C	No
POSIX	1003.2-1992; 1003.1-2001

Example

if (access("file.ext", W_OK)) return ERROR_CANNOT_WRITE; open("file.ext", O_RDWR);