Specifying the source data set: SYSIN

Define the data sets that contain your source code with the SYSIN DD statement:

//SYSIN    DD   DSN=datasetname,DISP=SHR

This data set contains the input to the assembler; that is, the assembler language source statements to be processed.

You can place your assembler source code in the input stream. To do this, use this SYSIN DD statement:

//SYSIN    DD   *

When you use the (*) DD parameter, the source code must follow the DD statement. If another job step follows the assembly, the EXEC statement for that step must follow the last source statement, or end-of-file (/*) statement.

The IBM-supplied High Level Assembler procedures do not contain the SYSIN DD statement. The DD statement for SYSIN must be provided in the input stream:

//STEP1    EXEC ASMAC
//SYSIN    DD   *
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assembler source statements
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/*