check_stack.h File Reference

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Functions
bool	check_stack_overrun (const THD *thd, long margin, unsigned char *dummy)
	Check stack for a overrun. More...

Function Documentation

check_stack_overrun()

bool check_stack_overrun	(	const THD *	thd,
		long	margin,
		unsigned char *	buf
	)

Check stack for a overrun.

Parameters

thd	Thread handler.
margin	Minimal acceptable unused space in the stack.
buf	See a note below.

Returns

false if success, true if error (reported).

Note

Note: The 'buf' parameter is necessary, and we must have code which uses it.

• Some of the fix_fields functions have a "dummy" buffer large enough for the corresponding execution. (Thus we only have to check in fix_fields.)
• Passing the buffer to check_stack_overrun() prevents the compiler from removing it.
• For -flto builds, the dummy buffer may be optimized away, so we need to write something into it.