167     f->f_buf = NULL;  in fill_file_fields()
615     PyMem_FREE(f->f_buf);  in drop_file_readahead()
616     f->f_buf = NULL;  in drop_file_readahead()
1082     if (f->f_buf != NULL &&  in file_read()
1084         f->f_buf[0] != '\0')  in file_read()
1164     if (f->f_buf != NULL &&  in file_readinto()
1166         f->f_buf[0] != '\0')  in file_readinto()
1575         if (fo->f_buf != NULL &&  in PyFile_GetLine()
1577             fo->f_buf[0] != '\0')  in PyFile_GetLine()
1667     if (f->f_buf != NULL &&  in file_readline()
1669         f->f_buf[0] != '\0')  in file_readline()
1702     if (f->f_buf != NULL &&  in file_readlines()
1704         f->f_buf[0] != '\0')  in file_readlines()
2361         readaheadbuffer rab = {f->f_buf, f->f_bufptr, f->f_bufend};  in file_iternext()
2362         f->f_buf = NULL;  in file_iternext()
2372         f->f_buf = rab.buf;  in file_iternext()