5 replies to this topic

[irancplusplus]

Hi
what does

return 0;

mean in main() function in a C(++) Console Application? how about

return 1;

or

return 2;

?
are they different?
what if 'return' is removed?

[Directive]

The value returned after main() is an indicator of how the program was terminated.

return 0; is traditionally used to indicate that the program terminated without errors. If the return is omitted, the function will automatically return 0. This is the only case I know of when omitting the return statement is allowed (not including void functions), but I think its best to include it for consistency's sake.

[WingedPanther]

It tells the OS/calling environment whether it terminated in a normal (0) state or a non-normal (other) state.

[irancplusplus]

how can one get what is returned in main using a batch file?

[Flying Dutchman]

On Unix systems you can with $? (bash), on Windows you can with %ERRORLEVEL%. See this for more info.

[dargueta]

Just an FYI, never omit the return statement in main, and never declare main as void. If you want I can explain the details, but it's kinda complicated. Just trust me on this.

These are always acceptable.

int main(int argc, char **argv)
int main()

This is non-standard and will only work on some compilers, but is a well-known extension.

int main(int argc, char **argv, char **env)

Don't do this.

void main( /* Any combinations of the above arguments */ )