qtcreator报错：fatal error: stdlib.h: No such file or directory

/usr/include/c++/8/cstdlib:75: error: stdlib.h: No such file or directory

In file included from /usr/include/c++/8/ext/string_conversions.h:41,

                 from /usr/include/c++/8/bits/basic_string.h:6400,

                 from /usr/include/c++/8/string:52,

                 from /usr/include/c++/8/stdexcept:39,

                 from /usr/include/c++/8/array:39,

                 from /usr/local/include/opencv4/opencv2/core/cvdef.h:781,

                 from /usr/local/include/opencv4/opencv2/core.hpp:52,

                 from /usr/local/include/opencv4/opencv2/opencv.hpp:52,

                 from main.cpp:3:

/usr/include/c++/8/cstdlib:75:15: fatal error: stdlib.h: No such file or directory

 #include_next <stdlib.h>

               ^~~~~~~~~~

原因，

由于前两天编译paddle项目的时候，采用的是gcc-8，而没有采用gcc-9，因此头文件的位置错误。

​​Linux中如何安装特定的gcc版本_高精度计算机视觉的博客​​

在/usr目录下搜索发现，有/usr/include/c++/8/stdlib.h，/usr/include/c++/9/stdlib.h也有/usr/include/stdlib.h，而我已经设置了默认编译器为gcc-8，因此，需要把默认的头文件地址去掉，项目的.pro设置如下，

TEMPLATE = app
CONFIG += console c++11
CONFIG -= app_bundle
CONFIG -= qt

SOURCES += \
        main.cpp

unix:!macx: LIBS += -L$$PWD/../../../../usr/local/lib/ -lopencv_world

INCLUDEPATH += $$PWD/../../../../usr/local/include/opencv4
DEPENDPATH += $$PWD/../../../../usr/local/include/opencv4

unix:!macx: LIBS += -L$$PWD/../../../../usr/lib/x86_64-linux-gnu/ -ltesseract

#INCLUDEPATH += $$PWD/../../../../usr/include
#DEPENDPATH += $$PWD/../../../../usr/include

INCLUDEPATH += /usr/include/c++/8

然后再编译，就没有问题了。

本文结束