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cprogram-entry-point

main() function without return type

Reading a document which is dated 1988, I found a main() function starting in this way:

main(argc, argv)
char *argv[];
{
    //some statements...
}

Surprisingly, I noticed there is no return type and even no data type for the arguments of the function - except for argv[] that is declared once more on the second line of the code.
Taking these considerations into account, my questions are: is that a valid syntax? If yes, why C language syntax is a bit different, nowadays?

Solution

  • That's the original, pre-1989 "K&R" function syntax. The return type (and even the parameter types) defaulted to int, and the parentheses contained only the names of the parameters, with their fully-typed declarations (if necessary) appearing before the first {.