Invalid file identifier. Use fopen to generate a valid file identifier.

I'm trying to open a file in this function, for the purpose of using it in another function. However, when I call on it, it gives me the error in fread, as stated in the title. I believe this is a result of fopen failing to open the file. However, I'm not certain how to fix it. Any help is appreciated. Thank you.

fileID = fopen(filename, 'rt');
[A,count]= fread(fileID,[2 inf], 'uint8');

[Eric Reinecke]

Did you check to make sure that filename is a valid file name and the filepath is included in it and/or matlab can find the file? Most errors with fread as you stated in the title occur in this way when Matlab can't find the file for whatever reason.

[Stephen23]

Please show us the displayed message:

[fileID,msg] = fopen(filename, 'rt');
assert(fileID>=3,msg)

[Kira Bruce]

the file name is PMHFIB_ORIGINAL.ATT. Is this file name invalid?

and I added the path below to the file in question, but I still recieved the same error.

addpath /Users/kira/desktop/PHYS4115Tables/'att';

[Kira Bruce]

Also, when i use teh code given to me by Stephen, it gives me the message: "no such file or directory".

What does this mean?

Answer 1

[per isakson]

Try

filespec = fullfile( "/Users/kira/desktop/PHYS4115Tables/'att'", filename );
fileID = fopen(filespec, 'rt');
assert(fileID>=3,msg)

And show us the displayed message.

What's 'att' ? The name of a subfolder?