LibPNG + Boost::GIL: 未找到 png_infopp_NULL答案

【问题标题】：LibPNG + Boost::GIL: png_infopp_NULL not foundLibPNG + Boost::GIL: 未找到 png_infopp_NULL
【发布时间】：2011-01-27 09:25:16
【问题描述】：

尝试使用 Boost::GIL PNG IO 支持编译我的文件时，我总是收到此错误：

（我正在运行 Mac OS X Leopard 和 Boost 1.42，LibPNG 1.4）

/usr/local/include/boost/gil/extension/io/png_io_private.hpp: In member function 'void boost::gil::detail::png_reader::init()':
/usr/local/include/boost/gil/extension/io/png_io_private.hpp:155: error: 'png_infopp_NULL' was not declared in this scope
/usr/local/include/boost/gil/extension/io/png_io_private.hpp:160: error: 'png_infopp_NULL' was not declared in this scope
/usr/local/include/boost/gil/extension/io/png_io_private.hpp: In destructor 'boost::gil::detail::png_reader::~png_reader()':
/usr/local/include/boost/gil/extension/io/png_io_private.hpp:174: error: 'png_infopp_NULL' was not declared in this scope
/usr/local/include/boost/gil/extension/io/png_io_private.hpp: In member function 'void boost::gil::detail::png_reader::apply(const View&)':
/usr/local/include/boost/gil/extension/io/png_io_private.hpp:186: error: 'int_p_NULL' was not declared in this scope
/usr/local/include/boost/gil/extension/io/png_io_private.hpp: In member function 'void boost::gil::detail::png_reader_color_convert<CC>::apply(const View&)':
/usr/local/include/boost/gil/extension/io/png_io_private.hpp:228: error: 'int_p_NULL' was not declared in this scope
/usr/local/include/boost/gil/extension/io/png_io_private.hpp: In member function 'void boost::gil::detail::png_writer::init()':
/usr/local/include/boost/gil/extension/io/png_io_private.hpp:317: error: 'png_infopp_NULL' was not declared in this scope

【问题讨论】：

标签： macos build libpng boost-gil

【解决方案1】：

最初我使用 libpng 1.4。我切换到 1.2 版，所有问题都消失了。

【讨论】：

【解决方案2】：

libpng 1.4 删除了png_infopp_NULL 和int_p_NULL 的定义。所以添加

#define png_infopp_NULL (png_infopp)NULL
#define int_p_NULL (int*)NULL

在您的代码中包含 GIL 标头之前。

【讨论】：

+1 谢谢。我考虑过这一点，但为了避免其他问题（如果有的话）恢复到 1.2。