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My application has potentially a huge number of arguments passed in and I want to avoid the memory of hit duplicating the arguments into a filtered list. I would like to filter them in place but I am pretty sure that messing with argv array itself, or any of the data it points to, is probably not advisable. Any suggestions?
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Once argv has been passed into the main method, you can treat it like any other C array - change it in place as you like, just be aware of what you're doing with it.
Short Answer: You can't. The way C organizes memory does not allow it. In your function int main(int, char**) you get two variables passed.
The syntax char** argv declares argv to be a pointer to a pointer to a character, that is, a pointer to a character array (a character string)--in other words, an array of character strings. You could also write this as char* argv[] .
The first element of the array, argv[0] , is a pointer to the character array that contains the program name or invocation name of the program that is being run from the command line. argv[1] indicates the first argument passed to the program, argv[2] the second argument, and so on.
The C99 standard says this about modifying argv (and argc):
The parameters argc and argv and the strings pointed to by the argv array shall be modifiable by the program, and retain their last-stored values between program startup and program termination.
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