ref: b0d33c09ff8fdb48e12843046033d1df68c9c54f
dir: /sys/src/libstdio/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->rp=f->wp=f->buf+(f->bufl==0?1:f->bufl); 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; } }