Thread: int main () and void main ()

Originally Posted by laserlight

However, if that (now anonymous) author's interpretation of the C standard is correct, then C code that uses void main() complies with the letter of the C standard, though it is not guaranteed by the standard to be portable.

The offending section from the C99 standard is;

5.1.2.2.1 Program startup
1 The function called at program startup is named main. The implementation declares no
prototype for this function. It shall be defined with a return type of int and with no
parameters:

Code:

int main(void) { /* ... */ }

or with two parameters (referred to here as argc and argv, though any names may be used, as they are local to the function in which they are declared):

Code:

int main(int argc, char *argv[]) { /* ... */ }

or equivalent;9) or in some other implementation-defined manner.
[/code]

where the 9) on the last line is a reference to footnote 9, which reads

9) Thus, int can be replaced by a typedef name defined as int, or the type of argv can be written as char ** argv, and so on.

I suppose your anonymous author is saying that, if the code examples and footnote reference are removed the sentence becomes "It shall be defined with a return type of int and with no parameters or with two parameters (referred to here as argc and argv, though any names may be used, as they are local to the function in which they are declared) or equivalent; or in some other implementation-defined manner."

If so, I disagree with your anonymous author's interpretation. A semi-colon is normally indicative of a continuation in formal reports (and an accepted standard is categorised as a formal report). For example, it will be used with a bulleted list to indicate that one item is related to another. Which means, in this sentence, that the semi-colon might as well not be there.

You're quite correct Dave. I was, however, responding to laserlights comments about an interpretation of the C99 standard. It may be a little OT in a C++ forum, but his comments were interesting to me (note to self: get out more!) and I didn't feel like breaking off and creating a thread in the C forum to pursue it.

In C89/90 and C++, the comments I made earlier apply. That extra snippet in the C99 standard muddies the water somewhat, but still (IMHO) doesn't make it legitimate for a programmer to use void main(), particularly if portability matters.