strtoi_(base_)generic()

Convert a string to a generic integer in C - the easy way!

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static inline
int strtoi_generic(const char *str,
                   <integer-type> *res);

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static inline
int strtoi_base_generic(const char *str,
                        int base,
                        <integer-type> *res);

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The main goal of this is to provide more easy to use and safer versions for string to integer conversions in C. With a cleaner separation of return values and error codes, without errno. In contrast to strto*() functions these two function-look-alikes/macros here need less surrounding wrapping/checks than strto*() functions. A single return value check is enough to verify correct parsing.

Notably you can provide a pointer to any kind of integer type for result storage - they will be able to check if the result would fit beforehand.

Yes, you heard right, generics in C!

Needs a modern C compiler for the C23 typeof() feature and the C11 _Generic() feature.

Example usage

Download the strtoi_generic.h and put it in the same directory as this example (or your code):

#include <stdio.h>
#include "strtoi_generic.h"

int main(int argc, char *argv[])
{
    char mystr[] = "123456789";
    long num;   // (un)signed char/short/int/long/long long/
                // (u)int{8/16/32/64}_t - whatever you want!
    int ret;

    ret = strtoi_generic(mystr, &num);
    if (ret < 0)
        printf("Error: %i\n", ret);
    else
        printf("OK, got: %li\n", num);

    return 0;
}

See strtoi_generic.h for a more detailed specification/documentation of strtoi_generic() and strtoi_base_generic().