Both JES2 and JES3 provide installation exit points for scanning the text created by the converter. You can use these exits to decide whether JES should cancel the job or allow it to continue normally. Your routine also can modify the C/I text. You cannot add text for an additional JCL statement, but you can add parameters to an existing JCL statement. You cannot delete the text for an entire JCL statement, but you can delete some of the parameters on that statement.

Use Caution When Modifying C/I Text. At the exit point at which the text is made available to your routine, the data already has been validated for syntax and for the proper keywords. The converter does not repeat this validation process after any modifications that you make. Therefore, there is no way to correct any error that a modification to the C/I text causes, and the job might fail at a later point in processing.

MVS™ creates the C/I text and uses it in its preparation for executing your job. IBM® recommends that you do not modify this text. If you decide to do so, use the following guidelines:

The interpreter needs to have all the correct lengths, the number of parameters, and the end-of-text key (X'FE') in order to parse the text string. You must ensure that the length of the entire text string (in the prefix) and the values for the length and number of parameters (in the key entries) are updated to reflect any modifications that you make.