I typically declare the main function's formal arguments as either int argc, char* argv[] or int argc, char** argv to take in the actual arguments from the command line. But I noticed a senior C programmer, who also happened to be a member of the ISO committee and co-author of the C23 revision, uses int argc, char* argv[argc+1], or int argc, char* argv[argc]. What is the point of doing that?
The following parameter declarations are equivalent:
int argc, char* argv[argc]int argc, char* argv[argc+1]int argc, char* argv[]int argc, char** argvThis equivalence is spelled out in section 6.7.6.3p7 of the C standard:
A declaration of a parameter as ‘‘array of type’’ shall be adjusted to ‘‘qualified pointer to type’’, where the type qualifiers (if any) are those specified within the
[and]of the array type derivation. If the keywordstaticalso appears within the[and]of the array type derivation, then for each call to the function, the value of the corresponding actual argument shall provide access to the first element of an array with at least as many elements as specified by the size expression
By the above paragraph, the first three cases are adjusted to be equivalent to the fourth. And as there's no static qualifier in any of those cases, it doesn't fall under any exceptions.
The developer likely did this as a form of internal documentation to illustrate the sizes of these arrays.