//line 4: warning: passing argument 1 of 'foo' from incompatible pointer typeCode:1 foo(const char **p) { } 2 main(int argc, char **argv) 3 { 4 foo(argv); 5 }
If u take the strlen function which has the prototype
U get ur code compiled without getting any warning when u pass char* argument. So y is there a warning in this case?Code:size_t strlen(const char *s);
see http://c-faq.com/ansi/constmismatch.html for a (fairly) full explanation
DavT
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On another note... I've always seen main() defined as:
but it would seem more logical to define it as:Code:int main( int argc, char* argv[] )
Is there any downside to making main() const-correct?Code:int main( int argc, const char* argv[] )
If want to make argv const, you should do this:Originally Posted by cpjust
But From what somebody said in this forum a while back, it actually is ok to modify the argv array. However, the buffers involved are only guaranteed to be large enough to hold the data they originally contain.Code:int main( int argc, const char * const *const argv )
Also, I would imagine some compilers may require argv to be nonconst, since it it easier to have one valid argument list for main, than several.
It is too clear and so it is hard to see.
A dunce once searched for fire with a lighted lantern.
Had he known what fire was,
He could have cooked his rice much sooner.
3 consts and a split double pointer?? What the hell is that?Code:const char * const *const argv
This I understand:
but why the 3rd const?Code:const char** const argv
The middle const is there to stop you modifying the pointers in the array, such as setting them to NULL, or swapping them.
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Advice: Take only as directed - If symptoms persist, please see your debugger
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