ref: bc7d74f09b53c39ada4e73ce73c01c6c0928f9f4
dir: /sys/src/libstdio/vsnprintf.c/
/*
* pANS stdio -- vsnprintf
*/
#include "iolib.h"
int vsnprintf(char *buf, int nbuf, const char *fmt, va_list args){
int n;
FILE *f=sopenw();
if(f==NULL)
return 0;
setvbuf(f, buf, _IOFBF, nbuf);
n=vfprintf(f, fmt, args);
sclose(f);
return n;
}