ref: 5c448c618a89ab8933838da1b5b97ed7c4a42e08
dir: /sys/src/ape/lib/ap/stdio/ungetc.c/
/* * pANS stdio -- ungetc */ #include "iolib.h" int ungetc(int c, FILE *f){ if(c==EOF) return EOF; switch(f->state){ default: /* WR */ f->state=ERR; return EOF; case CLOSED: case ERR: return EOF; case OPEN: _IO_setvbuf(f); case RDWR: case END: f->wp=f->buf; if(f->bufl==0) f->wp += 1; else f->wp += f->bufl; f->rp = f->wp; f->state=RD; case RD: if(f->rp==f->buf) return EOF; if(f->flags&STRING) f->rp--; else *--f->rp=c; return (char)c; } }