Passing Argument 1 discards qualifiers from pointer target type

My main function is as follows:

int main(int argc, char const *argv[])
{
    huffenc(argv[1]);
    return 0;
}

The compiler returns the warning:

huffenc.c:76: warning: passing argument 1 of ‘huffenc’ discards qualifiers from pointer target type

For reference, huffenc takes a char* input, and the function is executed, with the sample input "senselessness" via ./huffenc senselessness

What could this warning mean?