1 #include "stdio_impl.h" 2 3 /* The behavior of this function is undefined except when it is the first 4 * operation on the stream, so the presence or absence of locking is not 5 * observable in a program whose behavior is defined. Thus no locking is 6 * performed here. No allocation of buffers is performed, but a buffer 7 * provided by the caller is used as long as it is suitably sized. */ 8 setvbuf(FILE * restrict f,char * restrict buf,int type,size_t size)9int setvbuf(FILE *restrict f, char *restrict buf, int type, size_t size) 10 { 11 f->lbf = EOF; 12 13 if (type == _IONBF) { 14 f->buf_size = 0; 15 f->flags |= F_NOBUF; 16 } else if (type == _IOLBF || type == _IOFBF) { 17 if (buf && size >= UNGET) { 18 f->buf = (void *)(buf + UNGET); 19 f->buf_size = size - UNGET; 20 } 21 if (type == _IOLBF && f->buf_size) 22 f->lbf = '\n'; 23 f->flags &= ~F_NOBUF; 24 } else { 25 return -1; 26 } 27 28 f->flags |= F_SVB; 29 30 return 0; 31 } 32