C++ Access Function: Checking File Permissions
The access function is a function in the C/C++ standard library used to check if a file has specified permissions. It takes two parameters: the file path name to be checked and the permission mode to be checked.
Common permission modes include:
- F_OK: Check if the file exists
- R_OK: Check if the file is readable.
- W_OK: Check if the file is writable.
- X_OK: Checking if a file is executable.
The access function will attempt to check the specified file permissions using the current process’s actual user ID and effective user ID. It returns 0 if the file has the required permissions, or -1 otherwise.
The access function is commonly used to check the permissions of a file before accessing it, in order to ensure that the program has the necessary operation rights and prevent insufficient permission errors.
