ok, excuse me for asking stupid questions :-)... i had a short reading here: Inline (Using the GNU Compiler Collection (GCC))
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(i'm still reading but found this in the meantime)
Note that certain usages in a function definition can make it unsuitable for inline substitution.
Among these usages are: use of varargs, use of alloca, use of variable sized data types (see Variable Length), use of computed goto (see Labels as Values), use of nonlocal goto, and nested functions (see Nested Functions).
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