Function vasprintf

freebsd/libkern/asprintf.c:36–64

#include <machine/stdarg.h>

int
vasprintf(char **buf, struct malloc_type *mtp, const char *format, va_list va)
{
	int len, ret;
	va_list tmp_va;
	char dummy;

	va_copy(tmp_va, va);
	len = vsnprintf(&dummy, 0, format, tmp_va);
	va_end(tmp_va);
	if (len < 0) {
		*buf = NULL;
		return (len);
	}

	/* Account for null terminator. */
	len += 1;
	*buf = malloc(len, mtp, M_NOWAIT);
	if (*buf == NULL)
		return (-1);

	ret = vsnprintf(*buf, len, format, va);
	if (ret < 0) {
		free(*buf, mtp);
		*buf = NULL;
	}

	return (ret);
}

int
asprintf(char **buf, struct malloc_type *mtp, const char *format, ...)