source: bootcd/isolinux/syslinux-6.03/com32/lib/strerror.c

/*
 * strerror.c
 */

#include <string.h>

char *strerror(int errnum)
{
        static char message[32] = "error ";     /* enough for error 2^63-1 */
        char numbuf[32];
        char *p;
        unsigned int e = (unsigned int)errnum;

        extern const int sys_nerr;
        extern const char *const sys_errlist[];

        if (e < (unsigned int)sys_nerr && sys_errlist[e])
                return (char *)sys_errlist[e];

        p = numbuf + sizeof numbuf;
        *--p = '\0';

        do {
                *--p = (e % 10) + '0';
                e /= 10;
        } while (e);

        memcpy(message + 6, p, (numbuf + sizeof numbuf) - p);

        return message;
}