HLASM: V1R6 Language Ref

GBLA, GBLB, and GBLC instructionsGBLA, GBLB, and GBLC instructionsUse the GBLA, GBLB, and GBLC instructions to declare the global SETA, SETB,and SETC symbols you need. The SETA, SETB, and SETC symbols are assigned theinitial values of 0, 0, and null character string, respectively.,►►sequence_symbolGBLAGBLBGBLC▼variable_symbol►◄sequence_symbolis a sequence symbol.variable_symbolis a variable symbol, with or without the leading ampersand (&).These instructions can be used anywhere in the body of a macro definition or inthe open code portion of a source module.Any variable symbols declared in the operand field have a global scope. They canbe used as SET symbols anywhere after the pertinent GBLA, GBLB, or GBLCinstructions. However, they can be used only within those parts of a program inwhich they have been declared as global SET symbols; that is, in any macrodefinition and in open code.The assembler assigns an initial value to the SET symbol only when it processesthe first GBLA, GBLB, or GBLC instruction in which the symbol appears. LaterGBLA, GBLB, or GBLC instructions do not reassign an initial value to the SETsymbol.Multiple GBLx statements can declare the same variable symbol so long as onlyone declaration for a given symbol is encountered during the expansion of amacro.The following rules apply to the global SET variable symbol:v Within a macro definition, it must not be the same as any symbolic parameterdeclared in the prototype statement.v It must not be the same as any local variable symbol declared within the samelocal scope.v The same variable symbol must not be declared or used as two different types ofglobal SET symbol; for example, as a SETA or SETB symbol.v A global SET symbol should not begin with &SYS because these characters areused for system variable symbols.Subscripted global SET symbolsA global subscripted SET symbol is declared by the GBLA, GBLB, or GBLCinstruction.340 HLASM: V1R6 Language Ref