gcc.info: Return Address
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Getting the Return or Frame Address of a Function
These functions may be used to get information about the callers of a
function.
`__builtin_return_address (LEVEL)'
This function returns the return address of the current function,
or of one of its callers. The LEVEL argument is number of frames
to scan up the call stack. A value of `0' yields the return
address of the current function, a value of `1' yields the return
address of the caller of the current function, and so forth.
The LEVEL argument must be a constant integer.
On some machines it may be impossible to determine the return
address of any function other than the current one; in such cases,
or when the top of the stack has been reached, this function will
return `0'.
This function should only be used with a non-zero argument for
debugging purposes.
`__builtin_frame_address (LEVEL)'
This function is similar to `__builtin_return_address', but it
returns the address of the function frame rather than the return
address of the function. Calling `__builtin_frame_address' with a
value of `0' yields the frame address of the current function, a
value of `1' yields the frame address of the caller of the current
function, and so forth.
The frame is the area on the stack which holds local variables and
saved registers. The frame address is normally the address of the
first word pushed on to the stack by the function. However, the
exact definition depends upon the processor and the calling
convention. If the processor has a dedicated frame pointer
register, and the function has a frame, then
`__builtin_frame_address' will return the value of the frame
pointer register.
The caveats that apply to `__builtin_return_address' apply to this
function as well.
Created Wed Sep 1 16:42:20 2004 on bee with info_to_html version 0.9.6.