SET symbol specifications

SET symbols can be used in model statements, from which assembler language statements are generated, and in conditional assembly instructions. The three types of SET symbols are: SETA, SETB, and SETC. A SET symbol must be a valid variable symbol.

The rules for creating a SET symbol are:

The first character must be an ampersand (&)
The second character must be an alphabetic character
The remaining characters must be 0 to 61 alphanumeric
Do not set the first four characters to &SYS, which is used for system variable symbols

Examples:

&ARITHMETICVALUE439
&BOOLEAN
&C
&EASY_TO_READ

Local SET symbols need not be declared by explicit declarations. The assembler considers any undeclared variable symbol found in the name field of a SETx instruction as a local SET symbol, and implicitly declares it to have the type specified by the SETx instruction. The instruction that declares a SET symbol determines its scope and type.

The features of SET symbols and other types of variable symbols are compared in Table 1.

Table 1. Features of SET symbols and other types of variable symbols
Features	SETA, SETB, SETC symbols	Symbolic Parameters	System Variable Symbols
Can be used in: Open code Macro definitions	Yes Yes	No Yes	&SYSASM &SYSDATC &SYSDATE &SYSJOB &SYSM_HSEV &SYSM_SEV &SYSOPT_DBCS &SYSOPT_OPTABLE &SYSOPT_RENT &SYSOPT_XOBJECT &SYSPARM &SYSSTEP &SYSSTMT &SYSTEM_ID &SYSTIME &SYSVER All
Scope: Local Global	Yes Yes	Yes No	&SYSADATA_DSN &SYSADATA_MEMBER &SYSADATA_VOLUME &SYSCLOCK &SYSECT &SYSIN_DSN &SYSIN_MEMBER &SYSIN_VOLUME &SYSLIB_DSN &SYSLIB_MEMBER &SYSLIB_VOLUME &SYSLIN_DSN &SYSLIN_MEMBER &SYSLIN_VOLUME &SYSLIST &SYSLOC &SYSMAC &SYSNDX &SYSNEST &SYSPRINT_DSN &SYSPRINT_MEMBER &SYSPRINT_VOLUME &SYSPUNCH_DSN &SYSPUNCH_MEMBER &SYSPUNCH_VOLUME &SYSSEQF &SYSTERM_DSN &SYSTERM_MEMBER &SYSTERM_VOLUME &SYSASM &SYSDATC &SYSDATE &SYSJOB &SYSM_HSEV &SYSM_SEV &SYSOPT_DBCS &SYSOPT_OPTABLE &SYSOPT_RENT &SYSOPT_XOBJECT &SYSPARM &SYSSTEP &SYSSTMT &SYSTEM_ID &SYSTIME &SYSVER
Values can be changed within scope of symbol	Yes¹	No, read only value²	No, read only value²
Notes: The value assigned to a SET symbol can be changed by using the SETA, SETAF, SETB, SETC, or SETCF instruction within the declared or implied scope of the SET symbol. A symbolic parameter and the system variable symbols (except for &SYSSTMT, &SYSM_HSEV, and &SYSM_SEV) are assigned values that remain fixed throughout their scope. Wherever a SET symbol appears in a statement, the assembler replaces the symbol's current value with the value assigned to it.

SET symbols can be used in the name, operation, and operand fields of macro instructions. The value thus passed through the name field symbolic parameter into a macro definition is considered as a character string and is generated as such. If the COMPAT(SYSLIST) assembler option is specified, the value passed through an operand field symbolic into a macro definition is also considered a character string and is generated as such. However, if the COMPAT(SYSLIST) assembler option is not specified, SET symbols can be used to pass sublists into a macro definition.