ref: cd27c0cca2d72e467c26c78097b059b8e5a74c87
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;
}