# VScode+cmake 构建 EPICS C++ 编译环境

# 编译环境和所需组件

系统信息：Win10 64 位

Packages Source FUNC Docs
EPICS base-7.0.5 Official link EPICS base pvAccess C++
Visual Studio Code for windows Official link IDE For C++
CMake 3.19.3 Official link C++ tools For C++
mingw64 Official link Complier Cygwin

说明:

# EPICS base 的头文件和库文件位置

Name PATH
EPICS_BASE_DIR D:/EPICS/base-7.0.5/
EPICS_LIB_DIR D:/EPICS/base-7.0.5/lib/windows-x64-mingw
  • 顺利编译 EPICS base 后的 base 文件夹下， include 和 lib 两个子文件夹里就是所需的头文件和动态链接库文件.
  • include 文件夹结构目录
    1. compiler/gcc 里面 包括了编译时编译器的依赖头文件： compilerSpecific.h
    2. os/WIN32 文件夹里面包含了操作系统的依赖头文件
    3. pv 文件夹里为 Process Variable 相关的操作依赖头文件
    4. pva 文件下为 pvAccess 的依赖头文件
  • lib 文件夹结构目录

# CMakeLists.txt 编写

CMakeLists.txt 里面基础的部分可以通过 VS code 的 CMaketools 插件自动生成。

关于 EPICS base 的部分如下：

需要手动更改 EPICS base 和 Lib 文件的位置 

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# EPICS base directory
set(EPICS_BASE_DIR D:/EPICS/base-7.0.5/)
# EPICS lib directory
set(EPICS_LIB_DIR D:/EPICS/base-7.0.5/lib/windows-x64-mingw)

#include header file
include_directories(${EPICS_BASE_DIR}/include)
# for compiler
include_directories(${EPICS_BASE_DIR}/include/compiler/gcc)
# for operating system  
include_directories(${EPICS_BASE_DIR}/include/os/WIN32)

# link Lib directory
link_directories(${EPICS_LIB_DIR})

add_executable(${PROJECT_NAME} main.cpp)

# link EPICS dynamic libraries
target_link_libraries(${PROJECT_NAME} libpvAccess libca libCom 
libpvaClient libnt libpvData libpvDatabase libqsrv )

# EPICS pvAccessCPP C++ API 测试

EPICS base 的 C++ API 接口有 pvDataCPP、pvAccessCPP, 分别用于数据读取和 channel 访问。

API 文档

演示代码来自 pvAccessCPP api 文档里的 Simple Client Get Example

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#include <iostream>
#include <pva/client.h>
int main(int argc, char *argv[])
{
    try {
        if(argc<=1) {
            std::cerr<<"Usage: "<<argv[0]<<" <pvname>\n";
            return 1;
        }
        pvac::ClientProvider provider("pva");
        pvac::ClientChannel channel(provider.connect(argv[1]));
        std::cout<<channel.name()<<" : "<<channel.get()<<"*****end*****"<<"\n";
    }catch(std::exception& e){
        std::cerr<<"Error: "<<e.what()<<"\n";
        return 1;
    }
}

在 VS code 里面 build，编译通过后，启动 EPICS，运行程序，访问一个 PV 变量 $(PVhostName):ai1，结果如下：

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PS I:\Coding\EPICS_coding\PVget\build> ."I:/Coding/EPICS_coding/PVget/build/PVget.exe"
Usage: I:\Coding\EPICS_coding\PVget\build\PVget.exe <pvname>
PS I:\Coding\EPICS_coding\PVget\build> .\PVget.exe $(PVhostName):ai1
$(PVhostName):ai1 : epics:nt/NTScalar:1.0 
    double value 4
    alarm_t alarm
        int severity 1
        int status 1
        string message LOW
    time_t timeStamp
        long secondsPastEpoch 1651843923
        int nanoseconds 283817868
        int userTag 0
    structure display
        double limitLow 0
        double limitHigh 10
        string description "Analog input No. 1"
        string units Counts
        int precision 0
        enum_t form
            int index 0
            string[] choices [Default, String, Binary, Decimal, Hex, Exponential, Engineering]
    control_t control
        double limitLow 0
        double limitHigh 10
        double minStep 0
    valueAlarm_t valueAlarm
        boolean active false
        double lowWarningLimit 4
        double highAlarmLimit 8
        int lowAlarmSeverity 0
        int lowWarningSeverity 0
        int highWarningSeverity 0
        int highAlarmSeverity 0
        byte hysteresis 0
*****end*****

# 后记

纪念 EPICS 的主要开发者之一老爷子–Marty Kraimer
偶然在 EPICS 官网的 tech talk 看到了个帖子，才发现他是 EPICS 的早期开发者之一，30 多年奋战在一线，上面的 pvDataCPP 和 pvAccessCPP 的也是他开发的，他的 Github 主页上显示直到 2021 年 10 月 8 岁的 Marty 仍然还在提交 commit，令人钦佩。RIP RIP

  • “A Tribute to our Colleague Marty Kraimer”

Forgive the non-technical email. Marty passed away recently. As Marty has provided immeasurable support to this community, this seems like the most appropriate way to let everyone know. He was dedicated to building a collaboration on a code base - before there were any text books or scholarly papers or even a name for it - that was open-source. He was a prolific coder, open to help and take help from others. He was meticulous in the production of robust code that many would depend on to operate their facilities. Making mistakes and fixing them is great for making heroes. Making code that everyone depends on and no one ever notices is the work of an outstanding engineer. Marty was an outstanding engineer and he was tireless in this pursuit. He laid waste to many a keyboard with his pounding style. His contributions are fundamental to all of our successes. Have a beer to our colleague, benefactor and friend —

Marty Kraimer Github 主页