CMake & make & Library

Library

• static libraries
• shared libraries
• dynamically loaded libraries
• What is the effect of extern "C" in C++?
• One Definition Rule
• C++ Compiler Explained: What is the Compiler and How Do You Use it?
• C++ Compiler Operation
  The C++ compiler system
  The preprocessor: #define and #include

错误 corrupted size vs. prev_size

运行时报告如下错误，并产生 core 文件：

*** Error in `../lib/svd_bpack_gen': corrupted size vs. prev_size: 0x0000000000a58250 ***

进行 gdb 调试：gdb ../lib/svd_bpack_gen core.9954，报告：

Missing separate debuginfos, use: debuginfo-install glibc-2.17-322.el7_9.x86_64 libgcc-4.8.5-44.el7.x86_64 libstdc++-4.8.5-44.el7.x86_64 zlib-1.2.7-19.el7_9.x86_64

进行：sudo debuginfo-install glibc-2.17-322.el7_9.x86_64 libgcc-4.8.5-44.el7.x86_64 libstdc++-4.8.5-44.el7.x86_64 zlib-1.2.7-19.el7_9.x86_64 安装。

CMake

• CMAKE_DL_LIBS：类同 -ldl
• execute_process：执行命令。
• add_subdirectory：add_subdirectory(源文件目录 输出文件目录)
• Output Artifacts：要将编译结果文件存放何处，就看这里，比如：可执行文件，.a文件，.so文件等。
• find_library：

1. 下载 源码，以3.20.6为例。
2. 执行 ./bootstrap && make && sudo make install 进行安装。

安装后，执行 cmake，出现如下问题：
CMake Error: Could not find CMAKE_ROOT !!!
CMake has most likely not been installed correctly.
Modules directory not found in
/usr/local/bin
Segmentation fault

Do hash -r to clear the cache, then do cmake --version. 打印出 3.20.6，即告恢复正常。

• cmake -L .. For a list of all configure options, run cmake -L ..

C++ 的静态成员函数

• Why can static member function definitions not have the keyword 'static'?
  静态成员函数在声明时加 static 关键字，但在定义时不能加。上面这篇贴子说的很清楚。

编译选项

• Static and Dynamic ‘C’ Libraries：对编译命令 gcc, ar 有解释。
• position-independent code (PIC)
• -DCMAKE_BUILD_TYPE=Debug：编译 debug 版本。
• What is the idiomatic way in CMAKE to add the -fPIC compiler option?
• Difference between shared objects (.so), static libraries (.a), and DLL's (.so)?：共享对象、静态库、动态库？
• #pragma pack effect：It forces a particular alignment/packing of a struct, but like all #pragma directives they are implementation defined. 结构对齐的编译选项。

make

• make &> results.txt 可以把 make 编译结果输出到 results.txt 中。
• patsubst: 文本替换。
• notdir：类似于 basename，文件名函数。
• 一个 Makefile 文件示例

include ./Makefile.in                                                                                                    
DEST_PATH = /opt/bpack_gen/libexec
PWD := $(shell pwd)
BASENAME := $(shell basename ${PWD})
DATE := $(shell date +%Y%m%d)
$(info $(BASENAME) )
PROG = libbase_${BASENAME}.so.$(DATE)
LNPROG = libbase_${BASENAME}.so
LIBPROG = libbase_${BASENAME}.a

C 结构

• What is the meaning of "__attribute__((packed, aligned(4)))"；