ref: 4373c0b828f05aa6a765b13e8a9b111ed0b9a513
dir: /sys/src/libstdio/vsprintf.c/
/*
* pANS stdio -- vsprintf
*/
#include "iolib.h"
int vsprintf(char *buf, const char *fmt, va_list args){
int n;
FILE *f=sopenw();
if(f==NULL)
return 0;
setvbuf(f, buf, _IOFBF, 100000);
n=vfprintf(f, fmt, args);
sclose(f);
return n;
}