| SymAddTwin | Function (ROM Call 0x27F)

vat.h

HSym SymAddTwin (SYM_STR SymName);

Creates a twin symbol.

SymAddTwin creates a twin entry in the variable allocation table (VAT) for an existing symbol SymName. A twin symbol is, in fact, another entry in the VAT with the same variable name, but with a different handle. The TIOS creates twin symbols during execution of archived programs, just in front of the normal symbol in the VAT table (see EM_twinSymFromExtMem). A twin symbol is "stronger" that a normal symbol, i.e. existence of a twin symbol temporary hides the symbol with the same name, until the twin symbol is deleted. Twin symbols have the "twin" bit set in the VAT entry (see SYM_ENTRY for the structure of a VAT entry), but in the VAR-LINK menu, it is shown as "archived". SymAddTwin returns the same result as SymAdd (HS_NULL in case of an error). If the symbol SymName does not exist, this is also an error.

Uses: MakeHSym, SymCpy, SymFindPtr, HeapRealloc, memmove, _ds32s32
Used by: EM_twinSymFromExtMem