Message The use of the <spelling> option has prevented this redeclaration of "<variable>" from changing its linkage. The linkage will be that specified by the earlier declaration at <location>. Description In many cases, the compiler will allow a redeclaration of an item to change its linkage. For example, in most modes, if an object is declared with extern linkage and later with static linkage, the compiler will give it static linkage. This changing of linkage usually causes a warning to be issued. However, in cases where interfile optimization has been selected (-ifo on UNIX, /PLUS_LIST_OPTIMIZE on OpenVMS), the compiler cannot allow a later declaration to modify the linkage of a previous declaration. User Action Change all declarations to use the same linkage.