blocks|key|1044897|text|Win32软件开发工具包提供了三种形式的C运行时库：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1044898|*+LIBC.LIB+is+a+statically+linked+library+for+single-threaded+programs.
*+LIBCMT.LIB+is+a+statically+linked+library+that+supports+multithreaded+programs.
*+CRTDLL.LIB+is+an+import+library+for+CRTDLL.DLL+that+also+supports+multithreaded+programs.+CRTDLL.DLL+itself+is+part+of+Windows+NT.+|code-block|syntax|javascript|1044899|MicrosoftVisualCRT32位版本也包含这三种形式，但是，C%2B%2B中的MSVCRT.LIB是可再发行的。其名称取决于VC%2B%2B的版本(即MSVCRT10.DLL或MSVCRT20.DLL)。但是请注意，Win32s不支持MSVCRT10.DLL，而Win32s支持CRTDLL.LIB。MSVCRT20.DLL有两个版本:一个用于Windows+NT，另一个用于Win32s。|1044900|请参阅：http://support.microsoft.com/?scid=kb%253Ben-us%253B94248&x=12&y=9|offset|length|1044901|entityMap|0|LINK|mutability|MUTABLE|url|http://support.microsoft.com/?scid=kb%253Ben-us%253B94248&x=12&y=9^0|0|0|0|4|1Q|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|X|8|@]|9|@$K|Y|L|Z|1|10]]|A|$]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

There are three forms of the C Run-time library provided with the Win32 SDK:

<pre><code>* LIBC.LIB is a statically linked library for single-threaded programs.
* LIBCMT.LIB is a statically linked library that supports multithreaded programs.
* CRTDLL.LIB is an import library for CRTDLL.DLL that also supports multithreaded programs. CRTDLL.DLL itself is part of Windows NT. 
</code></pre>

Microsoft Visual C++ 32-bit edition contains these three forms as well, however, the CRT in a DLL is named MSVCRT.LIB. The DLL is redistributable. Its name depends on the version of VC++ (ie MSVCRT10.DLL or MSVCRT20.DLL). Note however, that MSVCRT10.DLL is not supported on Win32s, while CRTDLL.LIB is supported on Win32s. MSVCRT20.DLL comes in two versions: one for Windows NT and the other for Win32s.

see: <a href="http://support.microsoft.com/?scid=kb%3Ben-us%3B94248&amp;x=12&amp;y=9" rel="nofollow noreferrer">http://support.microsoft.com/?scid=kb%3Ben-us%3B94248&amp;x=12&amp;y=9</a>

blocks|key|1045633|text|如果您在从C或C%2B%2B编译的可执行文件上使用像Dependency+Walker这样的工具，您将看到它所依赖的DLL之一是MSVCRT.DLL。这是Microsoft+C运行时库。如果你用DW进一步研究MSVCRT.DLL，你会发现这是所有像printf()，put(0，get()，atoi()等函数的地方。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1045634|entityMap|0|LINK|mutability|MUTABLE|url|http://www.dependencywalker.com/^0|M|H|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

If you use a tool like <a href="http://www.dependencywalker.com/" rel="noreferrer">Dependency Walker</a> on an executable compiled from C or C++ , you will see that one of the the DLLs it is dependent on is MSVCRT.DLL. This is the Microsoft C Runtime Library. If you further examine MSVCRT.DLL with DW, you will see that this is where all the functions like printf(), puts(0, gets(), atoi() etc. live.

blocks|key|1045695|text|我自己也问过这个问题，几个小时以来我的大脑一直很痛。仍然没有找到任何真正有意义的东西。每个在主题中写东西的人都不能真正地“授课”。如果你想教一个人，选择一个人能理解的最基本的语言，这样他就不需要在处理一个话题时关心其他话题。因此，我给自己得出了一个似乎适合所有这些混乱的结论。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1045696|在C编程语言中，每个程序都以main()函数开头。其他语言可能会定义程序启动的其他函数。但是处理器不知道main()。处理器只知道由0和1的组合表示的预定义命令。|offset|length|style|CODE|1045697|在微处理器编程中，没有底层操作系统(Microsoft+Windows、Linux、MacOS等)，您需要通过设置在处理器已知的命令内迭代和跳转(循环、函数调用)的ProgramCounter+(PC)来明确地告诉处理器从哪里开始。您需要知道RAM有多大，需要设置程序堆栈的位置(局部变量)，以及堆的位置(动态变量)和全局变量的位置(我猜它被称为SSA?)在内存中。单个处理器一次只能执行一个程序。|1045698|这就是操作系统的用武之地。操作系统本身是一个在处理器上运行的程序。允许执行自定义代码的程序。通过在程序(加载到RAM中)的执行代码之间切换，一次运行多个程序。但是操作系统是一个程序，每个程序的编写方式都不同。简单地将您的自定义程序的代码放入RAM中将不会运行它，操作系统不知道它。你需要在注册你的程序的操作系统上调用函数，告诉操作系统程序需要多少内存，程序的入口点在哪里(C语言中的main()函数)。我猜这就是运行时库中的位置，它解释了为什么每个操作系统都需要一个特殊的库，因为这些只是程序本身，有不同的功能来做这些事情。|1045699|这也解释了为什么它不像.dll文件那样在运行时动态链接，即使它被称为运行时库。运行库需要静态链接，因为程序启动时需要它。运行库在运行时将自定义程序注入/连接到另一个程序(操作系统)。这真的会引起一些脑力衰竭..。|1045700|结论:运行时库命名失败。早期可能没有.dll+(在运行时链接)，也不存在理解差异的问题。但即使这是真的，这个名字也选错了。|1045701|运行时库的更好的名称可以是:+StartupLibrary/OSEntryLibrary/SystemConnectLibrary/OSConnectLibrary|1045702|希望我没弄错，准备改正/扩展。干杯。|1045703|entityMap^0|0|E|6|1G|6|1U|1|1W|1|0|2A|E|0|5B|6|0|B|4|0|I|4|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|W|8|@$D|X|E|Y|F|G]|$D|Z|E|10|F|G]|$D|11|E|12|F|G]|$D|13|E|14|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|15|8|@$D|16|E|17|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|18|8|@$D|19|E|1A|F|G]]|9|@]|A|$]]|$1|L|3|M|5|6|7|1B|8|@$D|1C|E|1D|F|G]]|9|@]|A|$]]|$1|N|3|O|5|6|7|1E|8|@$D|1F|E|1G|F|G]]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1H|8|@]|9|@]|A|$]]|$1|R|3|S|5|6|7|1I|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]]|U|$]]

I just asked this myself and was hurting my brain for some hours. Still did not find anything that really makes a point. Everybody that does write something to a topic is not able to actually &quot;teach&quot;. If you want to teach someone, take the most basic language a person understands, so he does not need to care about other topics when handling a topic. So I came to a conclusion for myself that seems to fit well in all this chaos.
In the programming language C, every program starts with the <code>main()</code> function.
Other languages might define other functions where the program starts. But a processor does not know the <code>main()</code>. A processor knows only predefined commands, represented by combinations of <code>0</code> and <code>1</code>.
In microprocessor programming, not having an underlying operating system (Microsoft Windows, Linux, MacOS,..), you need to tell the processor explicitly where to start by setting the <code>ProgramCounter</code> (PC) that iterates and jumps (loops, function calls) within the commands known to the processor. You need to know how big the RAM is, you need to set the position of the program stack (local variables), as well as the position of the heap (dynamic variables) and the location of global variables (I guess it was called SSA?) within the RAM.
A single processor can only execute one program at a time.
That's where the operating system comes in. The operating system itself is a program that runs on the processor. A program that allows the execution of custom code. Runs multiple programs at a time by switching between the execution codes of the programs (which are loaded into the RAM). But the operating system IS A PROGRAM, each program is written differently. Simply putting the code of your custom program into RAM will not run it, the operating system does not know it. You need to call functions on the operating system that registers your program, tell the operating system how much memory the program needs, where the entry point into the program is located (the <code>main()</code> function in case of C). And this is what I guess is located within the Runtime Library, and explains why you need a special library for each operating system, cause these are just programs themselves and have different functions to do these things.
This also explains why it is NOT dynamically linked at runtime as <code>.dll</code> files are, even if it is called a RUNTIME Library. The Runtime Library needs to be linked statically, because it is needed at startup of your program. The Runtime Library injects/connects your custom program into/to another program (the operating system) at RUNTIME. This really causes some brain f...
Conclusion:
RUNTIME Library is a fail in naming. There might not have been a <code>.dll</code> (linking at runtime) in the early times and the issue of understanding the difference simply did not exist. But even if this is true, the name is badly chosen.
Better names for the Runtime Library could be: StartupLibrary/OSEntryLibrary/SystemConnectLibrary/OSConnectLibrary
Hope I got it right, up for correction/expansion.
cheers.

What actually is a C runtime library and what is it used for? I was searching, Googling like a devil, but I couldn't find anything better than Microsoft's: "The Microsoft run-time library provides routines for programming for the Microsoft Windows operating system. These routines automate many common programming tasks that are not provided by the C and C++ languages."

OK, I get that, but for example, what is in <code>libcmt.lib</code>? What does it do? I thought that the C standard library was a part of C compiler. So is <code>libcmt.lib</code> Windows' implementation of C standard library functions to work under win32?

What is the C runtime library?

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什么是C运行时库，它是用来做什么的？我一直在搜索，像魔鬼一样用谷歌搜索，但我找不到比微软的更好的东西了：“微软的运行时库为Microsoft Windows操作系统提供了编程例程。这些例程自动化了许多C和C++语言没有提供的常见编程任务。”好的，我明白了，但是举个例子，libcmt.lib里面是什么？是干什么的呢？我认...

问什么是C运行时库？
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