sys/src/libstdio/setvbuf.c

   1 /*
   2  * pANS stdio -- setvbuf
   3  */
   4 #include "iolib.h"
   5 int setvbuf(FILE *f, char *buf, int mode, long size){
   6         if(f->state!=OPEN){
   7                 f->state=ERR;
   8                 return -1;
   9         }
  10         f->state=RDWR;
  11         switch(mode){
  12         case _IOLBF:
  13                 f->flags|=LINEBUF;
  14         case _IOFBF:
  15                 if(buf==0){
  16                         buf=malloc(size);
  17                         if(buf==0){
  18                                 f->state=ERR;
  19                                 return -1;
  20                         }
  21                         f->flags|=BALLOC;
  22                 }
  23                 f->bufl=size;
  24                 break;
  25         case _IONBF:
  26                 buf=f->unbuf;
  27                 f->bufl=0;
  28                 break;
  29         }
  30         f->rp=f->wp=f->lp=f->buf=buf;
  31         f->state=RDWR;
  32         return 0;
  33 }
  34 int _IO_setvbuf(FILE *f){
  35         static int isatty(int);
  36         if(f==stderr || (f==stdout && isatty(1)))
  37                 return setvbuf(f, (char *)0, _IOLBF, BUFSIZ);
  38         else return setvbuf(f, (char *)0, _IOFBF, BUFSIZ);
  39 }
  40 static int
  41 isatty(int fd)
  42 {
  43         char buf[64];
  44
  45         if(fd2path(fd, buf, sizeof buf) != 0)
  46                 return 0;
  47
  48         /* might be /mnt/term/dev/cons */
  49         return strlen(buf) >= 9 && strcmp(buf+strlen(buf)-9, "/dev/cons") == 0;
  50 }