file.access {base} | R Documentation |
Utility function to access information about files on the user's file systems.
file.access(names, mode = 0)
names |
character vector containing file names. |
mode |
integer specifying access mode required. |
The mode
value can be the exclusive or of the following values
Execute permission is ignored (always granted) under Windows, and all directories have both read and write permissions.
Please note that it is not good to use this function to test before
trying to open a file. On a multi-tasking system, it is possible that
the accessibility of a file will change between the time you call
file.access()
and the time you try to open the file, and in
recent Windows versions the underlying function in msvcrt.dll
sometimes returns inaccurate values. It is better to wrap
file open attempts in try
instead.
An integer vector with values 0
for success and -1
for failure.
This is intended as a replacement for the S-PLUS function
access
, a wrapper for the C function of the same name, which
explains the return value encoding. Note that
the return value is false for success.
fa <- file.access(dir(".")) table(fa) # count successes & failures