The EXIST specifier asks whether a file exists and can be opened. It takes the following form:
EXIST = ex
ex
Is a scalar default logical variable that is assigned one of the following values:
| .TRUE. | If the specified file exists and can be opened, or if the specified unit exists |
| .FALSE. | If the specified file or unit does not exist or if the file exists but cannot be opened |
The unit exists if it is a number in the range allowed by the processor.