*if ... *endif

*if, *else, *elseif, *endif. These commands create the conditionals. The format is a line which begins with *if followed by an expression between parenthesis. This expression will be written in C-language syntax, value return commands, will not begin with *, and its variables must be defined as integers or real numbers (see *format, *intformat, *realformat), with the exception of strcmp and strcasecmp. It can include relational as well as arithmetic operators inside the expressions.

The following are valid examples of the use of the conditionals:

*if((fabs(loopvar)/4)<1.e+2)
*if((p3<p2)||p4)
*if((strcasecmp(cond(1),"XLoad")==0)&&(cond(2)!=0))

The first example is a numerical example where the condition is satisfied for the values of the loop under 400, while the other two are logical operators; in the first of these two, the condition is satisfied when p3<p2 or p4 is different from 0, and in the second, when the first field of the condition is called XLoad (with this particular writing) and the second is not null.

If the checked condition is true, GiD will write all the lines until it finds the corresponding *else, *elseif or *endif (*end is equivalent to *endif after *if). *else or *elseif are optional and require the writing of all the lines until the corresponding *endif, but only when the condition given by *if is false. If either *else or *elseif is present, it must be written between *if and *endif. The conditionals can be nested among them.

The behaviour of *elseif is identical to the behaviour of *else with the addition of a new condition:

*if(GenData(31,int)==1)   
...(1) 
*elseif(GenData(31,int)==2)   
...(2) 
*else   
...(3) 
*endif

In the previous example, the body of the first condition (written as 1) will be written to the data file if GenData(31,int) is 1, the body of the second condition (written as 2) will be written to the data file if GenData(31,int) is 2, and if neither of these is true, the body of the third condition (written as 3) will be written to the data file.

Note: A conditional can also be written in the middle of a line. To do this, begin another line and write the conditional by means of the command *\.