using "sgrep 'C_FUNCS'" on the following file:
int i = f();
void f (void)
{}

Gives not the expected result (==>outputs nothing).
However, it does on the following file:
/* int i = f(); */
void f (void)
{}
==>outputs "void f (void)"

Furthermore, the following command gives the expected result:
containing C_PAREN' trace_min.c | sgrep '"\n" _. "\n" not containing ";"'

It is not clear whether the bug is in the macro or in the program.

Please confirm it can be reproduced.

Suggested fix: Warn user who read man (in BUGS section) if appropriate.