Because POSIX behaviour is obnoxious sometimes. A super thin syscall wrapper so posix will never bother us again.

fuposix.c

#include <stdio.h>
#include <unistd.h>
#include <string.h>


typedef int (*scfunc)(const char *, const char *);

struct SysCall {
    char* name;
    scfunc func;
};

struct SysCall syscalls[] = {
    {"rename", rename},
    {"link", link},
    {"symlink", symlink}
};

int main (int argc, char **argv) {
    if (argc < 2) {
        printf("Usage: %s funcname arg1 arg2\n", argv[0]);
        return -1;
    }
    char *a1 = argv[2];
    char *a2 = argv[3];
    struct SysCall sc;
    for (int i = 0; i < sizeof(syscalls) / sizeof(struct SysCall); ++i) {
        sc = syscalls[i];
        if (!strcmp(argv[1], sc.name)) {
            // printf("%s(%s, %s)\n", argv[1], a1, a2);
            int res = sc.func(a1, a2);
            if (res != 0) {
                puts(strerror(res));
            }
            return 0;
        }
    }
    puts("Could not find supported syscall");
}