HLASM: V1R6 Language Ref

Beginning of a source moduleCSECT, RSECT, and START start a possibly named control section. The otherstatements start an unnamed control section.These instructions are always considered a part of the control section in which theyappear.The statements copied into a source module by a COPY instruction determinewhether it initiates the first control section. The PROFILE option causes theassembler to generate a COPY statement as the first statement after any ICTL or*PROCESS statements.The DSECT, COM, and DXD instructions initiate reference control sections and donot establish the first executable section.Any instructions copied by a COPY instruction, or generated by the processing of amacro instruction before the first section, must belong to one of the groups ofinstructions shown above. Any other instructions cause the assembler to establishthe first section.All the instructions or groups of instructions listed above can also appear as partof a section.If you specify the PROFILE assembler option the assembler generates a COPYstatement as the first statement in the assembly after any ICTL or *PROCESSstatements. The copy member should not contain any ICTL or *PROCESSstatements.Unnamed sectionThe unnamed section is an executable section that can be initiated in one of thefollowing two ways:v By coding a START, CSECT, or RSECT instruction without a name entryv By coding any instruction, other than the START, CSECT, or RSECT instruction,that initiates the first executable sectionAn unnamed control section is sometimes referred to as private code. Private codesections are sometimes difficult to manage with other system components such aslinkers and configuration management tools. Avoiding their use is recommended.(Zero-length private code sections are sometimes ignored or discarded by systemlinkers.)All sections should be given names so they can be referred to symbolically:v Within a source modulev In EXTRN and WXTRN instructionsv in linker control statements for section ordering and replacement, and forlinkage between source modulesUnnamed common control sections or dummy control sections can be defined ifthe name entry is omitted from a COM or DSECT instruction.If you include an AMODE or RMODE instruction in the assembly and leave thename field blank, you must provide an unnamed control section.54 HLASM: V1R6 Language Ref