检测同一变量使用不同访问路径的情况
理由对同一元素的不同访问会降低程序的可读性和可维护性。我们建议对库、全局变量列表和枚举统一使用{attribute 'qualified-only'} 。这将强制使用完全合格的访问权限。
重要性：低
示例
VAR_GLOBAL iTemp:INT; instPOU:POU; END_VAR FUNCTION_BLOCK POU VAR a:INT; END_VAR a := INT#1; PROGRAM SA0042 VAR ptiTemp:POINTER TO INT; sTemp:STRING; END_VAR ptiTemp := ADR(iTemp); ptiTemp^:= INT#1; iTemp:= INT#2; // SA0042 - direct access on variable GVL.iTemp := INT#3; // SA0042 - access on variable via GVL sTemp := CONCAT( 'ab', 'cd'); // SA0042 - direct access on function sTemp := Standard.CONCAT( 'ab', 'cd'); // SA0042 - access on function via Standard instPOU(); // SA0042 - direct access on POU instance GVL.instPOU(); // SA0042 - access via GVL --> SA0042: Different access paths for 'CONCAT' --> SA0042: Different access paths for 'Standard.CONCAT' --> SA0042: Different access paths for 'instPOU' --> SA0042: Different access paths for 'GVL.instPOU' --> SA0042: Different access paths for 'iTemp' --> SA0042: Different access paths for 'GVL.iTemp'