-int bf_read (BFile bf, zint no, int offset, int nbytes, void *buf);
+int bf_read2(BFile bf, zint no, int offset, int nbytes, void *buf)
+ ZEBRA_GCC_ATTR((warn_unused_result));
+
+
+/** \brief writes block of bytes to file (may call exit)
+ \param bf block file handle
+ \param no block no
+ \param offset within block
+ \param nbytes number of bytes to write
+ \param buf buffer to write
+ \retval 0 success (block could be written)
+
+ This function can not return a failure. System calls exit(1)
+ if write failed.
+ */
+YAZ_EXPORT
+int bf_write(BFile bf, zint no, int offset, int nbytes, const void *buf);
+