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Message-ID: <55E9D456.9040301@gmail.com>
Date: Fri, 04 Sep 2015 11:26:46 -0600
From: Martin Sebor <msebor@gmail.com>
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To: "sc22wg14@open-std.org" <sc22wg14@open-std.org>
Subject: valid uses of main
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5.1.2.2.2 Program execution says:

   In a hosted environment, a program may use all the functions,
   macros, type definitions, and objects described in the library
   clause (clause 7).

5.1.2.2.3 Program termination the goes on to say:

   If the return type of the main function is a type compatible
   with int, a return from the initial call to the main function
   is equivalent to calling the exit function with the value
   returned by the main function as its argument; ...

Is it correct to interpret the first paragraph as a requirement
on programs (in hosted environments) that they must not call or
otherwise use main, and conversely on (hosted) implementations
that they must diagnose such uses?

I ask because the phrase "initial call to the main function"
suggests that there may be other calls to main besides the one
at program startup.  A similar phrase is also used in 7.21.3
Files: "If the main function returns to its original caller,
all open files are closed..." There also is no mention in
Annex J of programs that call main having undefined behavior.
But this interpretation (i.e., permission to use main) would
then contradict 5.1.2.2.2.

Thanks
Martin

PS For comparison, C++ contains an explicit requirement that

   The function main shall not be used within a program.

obviating the question above for that language.