You can only specify one numeric file format for all unformatted file unit numbers using this method unless you also use one of the environment variable methods or OPEN statement CONVERT keyword method.
You specify the numeric format at compile time and must compile all routines under the same OPTIONS statement CONVERT keyword qualifier.
The environment variable methods and the OPEN statement CONVERT method take precedence over this method. For instance, you might use the environment variable FORT_CONVERTn method or OPEN statement CONVERT method to specify each unit number that will use a format other than that specified using the ifort option method.
This method takes precedence over the convert keyword compiler option method.
You can use OPTIONS statements to specify the appropriate floating-point formats (in memory and in unformatted files) instead of using the corresponding ifort command qualifiers. For example, to use VAX F_floating and G_floating as the unformatted file format, specify the following OPTIONS statement:
Because this method affects all unit numbers, you cannot read data in one format and write it in another format, unless you use it in combination with one of the environment variable methods or the OPEN statement CONVERT keyword method to specify a different format for a particular unit number.