__builtin_return_address(3) - NetBSD Manual Pages

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__BUILTIN_RETURN_ADD... NetBSD Library Functions Manual__BUILTIN_RETURN_ADD...


NAME

     __builtin_return_address -- the return address of a function


SYNOPSIS

     void *
     __builtin_return_address(unsigned int level);

     void *
     __builtin_frame_address(unsigned int level);


DESCRIPTION

     The __builtin_return_address() is a GNU extension for obtaining the
     return address of the current function or one of the callers of the cur-
     rent function.

     The parameter level specifies the number of frames that should be scanned
     up in the call stack.  A value 0 returns the address of the current func-
     tion, a value 1 requests the address of the caller of the current func-
     tion, a value 2 asks for the address of the caller's caller, and so
     forth.  If the top of the call stack has been reached, the function will
     return 0.  Note also that on some architectures it is only possible to
     determine the address of the current function.  In such cases a value 0
     is returned.  Thus, it is usually safe to only use the value 0 for level.

     The __builtin_frame_address() behaves similarly, but returns the address
     of the function frame rather than the return address of the function.


SEE ALSO

     gcc(1), __builtin_object_size(3)


CAVEATS

     These are non-standard, compiler-specific extensions.

NetBSD 6.0                     December 19, 2010                    NetBSD 6.0