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C++ API

: nargout ()
: nargout (fcn)

Report the number of output arguments from a function.

Called from within a function, return the number of values the caller expects to receive. At the top level, nargout with no argument is undefined and will produce an error.

If called with the optional argument fcn—a function name or handle—return the number of declared output values that the function can produce.

If the final output argument is varargout the returned value is negative.

For example, 

f ()

will cause nargout to return 0 inside the function f and 

[s, t] = f ()

will cause nargout to return 2 inside the function f.

In the second usage, 

nargout (@histc)   # or nargout ("histc") using a string input

will return 2, because histc has two outputs, whereas 

nargout (@imread)

will return -2, because imread has two outputs and the second is varargout.

Programming Note. nargout does not work for built-in functions and returns -1 for all anonymous functions.

See also: nargin, varargout, isargout, nthargout.

Package: octave