Based on put file status

Conditionals may be placed in the GAMS code to do particular things only if some put file is open.  Such commands are of the form

$If putopen gamsstatement

$If not putopen gamsstatement

where the first of the two syntax alternatives yields a true conditional if both a file statement and at least one put statement have been executed.  Note this does not guarantee that a file will be open at runtime.

Example:

(putopen.gms)

$If putopen $goto around

file myfile;

put myfile;

$label around