Getting warnings for using void * while trying to recode printf

I’m trying to set up an array of functions that takes in functions that need different variables (for example, my_putchar needs a char while my_put_nbr needs an int), so I just decided to define it using a void *. While it does work it gives me warnings when I compile.

#include "stdarg.h"
#include "my.h"

int put_perc(void)
{
    my_putchar('%');
}

int read_print(const char *s, int i, va_list args)
{
    int k = 0;
    char guide[] = "cdis%f";
    int (*functions[])(void *) = {my_putchar, my_put_nbr,
        my_put_nbr, my_putstr, put_perc, my_put_float};

    for (k = 0; s[i + 1] != guide[k]; k++);
    functions[k](va_arg(args, void *));
}

void mini_printf(const char *s, ...)
{
    int k = 0;
    va_list args;
    char guide[] = "cdis%";

    va_start(args, s);
    for (int i = 0; i < my_strlen(s); i++) {
        if (s[i] == '%') {
            read_print(s, i, args);
            i++;
        } else {
            my_putchar(s[i]);
        }
    }
    va_end(args);
}

void main(void)
{
    mini_printf("%s %s %s letter is %c followed by %d and %i.\nfloats %f  \nlets also test     this out, %s 100%%\n", "come", "on", "WORK", 'h', 58, 12, 55.756567575658, "this should work");
}

These are the warnings I get.

my_printf.c: In function ‘read_print’:
my_printf.c:20:35: warning: initialization of ‘int (*)(void *)’ from incompatible pointer type ‘void (*)(char)’ [-Wincompatible-pointer-types]
   20 |     int (*functions[])(void *) = {my_putchar, my_put_nbr,
      |                                   ^~~~~~~~~~
my_printf.c:20:35: note: (near initialization for ‘functions[0]’)
my_printf.c:20:47: warning: initialization of ‘int (*)(void *)’ from incompatible pointer type ‘int (*)(int)’ [-Wincompatible-pointer-types]
   20 |     int (*functions[])(void *) = {my_putchar, my_put_nbr,
      |                                               ^~~~~~~~~~
my_printf.c:20:47: note: (near initialization for ‘functions[1]’)
my_printf.c:21:9: warning: initialization of ‘int (*)(void *)’ from incompatible pointer type ‘int (*)(int)’ [-Wincompatible-pointer-types]
   21 |         my_put_nbr, my_putstr, put_perc, my_put_float};
      |         ^~~~~~~~~~
my_printf.c:21:9: note: (near initialization for ‘functions[2]’)
my_printf.c:21:21: warning: initialization of ‘int (*)(void *)’ from incompatible pointer type ‘int (*)(const char *)’ [-Wincompatible-pointer-types]
   21 |         my_put_nbr, my_putstr, put_perc, my_put_float};
      |                     ^~~~~~~~~
my_printf.c:21:21: note: (near initialization for ‘functions[3]’)
my_printf.c:21:32: warning: initialization of ‘int (*)(void *)’ from incompatible pointer type ‘int (*)(void)’ [-Wincompatible-pointer-types]
   21 |         my_put_nbr, my_putstr, put_perc, my_put_float};
      |                                ^~~~~~~~
my_printf.c:21:32: note: (near initialization for ‘functions[4]’)
my_printf.c:21:42: warning: initialization of ‘int (*)(void *)’ from incompatible pointer type ‘int (*)(double)’ [-Wincompatible-pointer-types]
   21 |         my_put_nbr, my_putstr, put_perc, my_put_float};
      |                                          ^~~~~~~~~~~~
my_printf.c:21:42: note: (near initialization for ‘functions[5]’)

I don’t really know how to fix this because I just thought void * acted as a catchall for variable types. (this is only my 3rd week of coding so im still not that experienced)

You need to sign in to view this answers

Related Post