golang

const (
	O_RDONLY = os.O_RDONLY // open the file read-only.
	O_WRONLY = os.O_WRONLY // open the file write-only.
	O_RDWR   = os.O_RDWR   // open the file read-write.
	// The remaining values may be or'ed in to control behavior.
	O_APPEND = os.O_APPEND // append data to the file when writing.
	O_CREATE = os.O_CREATE // create a new file if none exists.
	O_EXCL   = os.O_EXCL   // used with O_CREATE, file must not exist.
	O_SYNC   = os.O_SYNC   // open for synchronous I/O.
	O_TRUNC  = os.O_TRUNC  // truncate regular writable file when opened.

	// O_FILE_FLAG_NO_RO_ATTR skips setting a file's read-only attribute on Windows.
	// We set this data empirically, based on the values listed at
	// https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea and
	// https://learn.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants
	O_FILE_FLAG_NO_RO_ATTR = 0x00010000
)