You must precede this keyword with ce on the command line.Predefined macro
This keyword checks the status of the argument symbol_name, to see whether the variable is in scope, and whether it can be referenced. The value returned by isalive specifies the current status of the variable.
Syntax:
int isalive (symbol_name)
void symbol_name;
You must precede this keyword with ce on the command line.
where:
symbol_name The variable name used for the symbol that isalive tests the scope of.
Return Value
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integer |
The return value can have one of four values [ -1, 0, 1, 2 ] |
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-1 |
Symbol does not exist |
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0 |
Symbol not currently active (cannot be referenced, said to be out of scope). |
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1 |
Symbol currently active (symbol is part of local procedure, also called an automatic variable). |
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2 |
Available on the stack (symbol is not part of local procedure, also called an external (active), global (active), or static automatic variable (inactive, but containing stored memory contents) ). |
Rules
The argument of isalive must be a variable that has no return value. The argument cannot be a function.
Examples
You can use the following syntax for the isalive macro when checking the status of a variable used in its argument. Note: the keywords CEXPRESSION and CE are equivalent.
CEXPRESSION isalive(xxx)
/* Returns -1 if the symbol xxx does
not exist. */
ADD var1
CE isalive(var1)
/* Returns 1 since var1 is defined and active. */