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#define _GNU_SOURCE
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#define GUESS 240U
int vasprintf(char **s, const char *fmt, va_list ap)
{
va_list ap2;
char *a;
int l=GUESS;
if (!(a=malloc(GUESS))) return -1;
va_copy(ap2, ap);
l=vsnprintf(a, GUESS, fmt, ap2);
va_end(ap2);
if (l<GUESS) {
char *b = realloc(a, l+1U);
*s = b ? b : a;
return l;
}
free(a);
if (l<0 || !(*s=malloc(l+1U))) return -1;
return vsnprintf(*s, l+1U, fmt, ap);
}
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