HLASM Language Reference

The CSECT instruction can be used anywhere in a source module to initiate or
continue a section. For more information about the CSECT instruction, see
“CSECT Instruction” on page 123.
Like the CSECT instruction, the RSECT instruction can be used anywhere in a
source module to initiate or continue a section. Unlike the CSECT instruction,
however, the RSECT instruction causes the assembler to check the coding in
the section for possible violations of reenterability. For more information about
the RSECT instruction, see “RSECT Instruction” on page 212.
A section can also be initiated as an unnamed section, or private code, without
using the START, CSECT, or RSECT instruction. For more information, see
“Unnamed Section” on page 55.
First Section
| Before you initiate the first section in your source module, you may code only
certain instructions. The following information lists those instructions that initiate
the first section, and those instructions that may precede the first section.
| What must appear before the first section: The ICTL instruction, if specified,
must be the first statement in a source module.
*PROCESS statements must precede all other statements in a source module,
except the ICTL instruction. There is a limit of 10 *PROCESS statements allowed
in a source module. Additional *PROCESS statements are treated as assembler
comment statements. See page 102 for a description of the *PROCESS statement.
| What can optionally appear before the first executable control section: The
instructions or groups of instructions that can optionally be specified before the first
| executable control section are:
The following assembler instructions:
ACONTROL ADATA AINSERT ALIAS CEJECT COPY
DXD EJECT ENTRY EXITCTL EXTRN ISEQ
MACRO MEND MEXIT POP PRINT PUNCH
PUSH REPRO SPACE TITLE WXTRN XATTR
Comment statements, including macro format comment statements
Any statement which is part of an inline macro definition
Common control sections
Dummy control sections
Any conditional assembly instruction
| Macro instructions that do not generate statements that establish the first
| section
The above instructions or groups of instructions belong to a source module, but are
not considered part of an executable section.
54 HLASM V1R5 Language Reference