Jonathan Wakely
5342e3cc44
When configured with --enable-cstdio=stdio_pure we need to consistently use fseek and not mix seeks on the file descriptor with reads and writes on the FILE stream. There are also a number of bugs related to error handling and return values, because fread and fwrite return 0 on error, not -1, and fseek returns 0 on success, not the file offset. libstdc++-v3/ChangeLog: PR libstdc++/110574 * acinclude.m4 (GLIBCXX_CHECK_LFS): Check for fseeko and ftello and define _GLIBCXX_USE_FSEEKO_FTELLO. * config.h.in: Regenerate. * configure: Regenerate. * config/io/basic_file_stdio.cc (xwrite) [_GLIBCXX_USE_STDIO_PURE]: Check for fwrite error correctly. (__basic_file<char>::xsgetn) [_GLIBCXX_USE_STDIO_PURE]: Check for fread error correctly. (get_file_offset): New function. (__basic_file<char>::seekoff) [_GLIBCXX_USE_STDIO_PURE]: Use fseeko if available. Use get_file_offset instead of return value of fseek. (__basic_file<char>::showmanyc): Use get_file_offset. (cherry picked from commit 2f6bbc9a7d9a62423c576e13dc46323fe16ba5aa)
file: libstdc++-v3/README New users may wish to point their web browsers to the file index.html in the 'doc/html' subdirectory. It contains brief building instructions and notes on how to configure the library in interesting ways.