access

Arguments

Returns

Zero is returned if the access mode is valid, otherwise -1 is returned and the errno is set.

Description

This function checks a file for the following permissions. Two or more permissions in bitwise OR combinations can be checked at one time.

• R_OK Test for read permission.

• W_OK Test for write permission.

• X_OK Test for execute permission.

• F_OK Test for existence of file.

The library "const/Filesys.lsp" must be required to use the constants listed above.

Example

    Gamma> require_lisp("const/Filesys");
    "/usr/cogent/lib/const/Filesys.lsp"
    Gamma> system("touch /tmp/access_test");
    0
    Gamma> system("chmod a=rx /tmp/access_test");
    0
    Gamma> access("/tmp/access_test", R_OK|X_OK);
    0
    Gamma> access("/tmp/access_test", W_OK);
    -1
    Gamma> 
    		

See the Starting qserve and nserve section of the Common Functions chapter (Tutorial One), or the Start a Process section of the Common Functions for Any Program chapter (Tutorial Two), or the Linux, QNX 4, or QNX 6 section of the Abstracted Functions chapter in the Cogent Tools Demo and Tutorials book for examples of this function used in context.

See Also

is_busy, is_file, is_readable, is_writable, errno