子进程从其父进程继承了一个句柄但未能写入其中

您可能正在使用可继承的文件句柄创建子进程，但实际上并没有告诉子进程该句柄的值是什么！孩子正在 中寻找该值argv[1]，但您显示的代码未在该参数中传递任何值！即使有，您也没有正确检索值。

命令行参数始终是字符串，argv[1]指向以空字符结尾的字符串的指针也是如此，而不是句柄。当你把它放在命令行上时，你必须将句柄指针转换为字符串表示，然后在处理命令行时必须将该字符串解析回指针。

尝试更像这样的事情：

流程一：

#include <Windows.h>
#include <process.h>
#include <stdio.h>
#include <tchar.h>

int _tmain(int argc, _TCHAR* argv[])
{
    SECURITY_ATTRIBUTES sec_attr = {};
    sec_attr.nLength = sizeof(sec_attr);
    sec_attr.bInheritHandle = TRUE;
    sec_attr.lpSecurityDescriptor = 0;

    //argv[1] - the name of the file I want to create
    HANDLE h = CreateFile(argv[1], GENERIC_READ | GENERIC_WRITE, FILE_SHARE_WRITE | FILE_SHARE_READ, &sec_attr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
    if (h == INVALID_HANDLE_VALUE)
    {
        // handle the error ...
        return 1;
    }

    STARTUPINFO sinfo;      
    ZeroMemory(&sinfo, sizeof(sinfo));
    sinfo.cb = sizeof(sinfo);

    PROCESS_INFORMATION pinfo;
    ZeroMemory(&pinfo, sizeof(pinfo));

    _TCHAR cmd[MAX_PATH + 16] = {};
    _tsprintf(cmd, _T("\"%s\" %p"), _T("PATH to process 2"), h);

    // TODO: consider using STARTUPINFOEX instead so the child inherits
    // ONLY the file handle and not ALL inheritable handles it doesn't
    // care about:
    //
    // Programmatically controlling which handles are inherited by new processes in Win32
    // https://blogs.msdn.microsoft.com/oldnewthing/20111216-00/?p=8873
    //
    if (!CreateProcess(0, cmd, 0, 0, TRUE, NORMAL_PRIORITY_CLASS, 0, 0, &sinfo, &pinfo))
    {
        // handle the error ...
        return 1;
    }

    CloseHandle(pinfo.hThread);
    CloseHandle(pinfo.hProcess);

    char c = '1';
    DWORD w;
    WriteFile(h, &c, 1, &w, 0);
    ...

    CloseHandle(h);
    return 0;
}

过程2：

#include <Windows.h>
#include <process.h>
#include <stdio.h>
#include <tchar.h>

int _tmain(int argc, _TCHAR* argv[]) 
{
    if (argc < 2)
    { 
        // ...
        return 1;
    }

    //argv[1] - string representation of a handle to an open file
    HANDLE h = INVALID_HANDLE_VALUE;
    _stscanf(argv[1], _T("%p"), &h);

    char c = '2';
    DWORD w;
    WriteFile(h, &c, 1, &w, 0);
    ...

    CloseHandle(h);
    return 0;
}

话虽如此，拥有两个线程，更不用说两个进程，共享一个文件句柄并不是一个好主意。给定的文件句柄中只有 1 个读/写位置，因此共享该句柄会冒着线程/进程相互交错的风险，除非您在它们之间提供某种同步，以便只有一个人可以同时访问该文件时间。

考虑将目标文件名传递给子进程，并让它打开自己唯一的文件句柄，例如：

流程一：

#include <Windows.h>
#include <process.h>
#include <stdio.h>
#include <tchar.h>

int _tmain(int argc, _TCHAR* argv[])
{
    if (argc < 2)
    { 
        // ...
        return 1;
    }

    //argv[1] - the name of the file I want to create
    HANDLE h = CreateFile(argv[1], GENERIC_READ | GENERIC_WRITE, FILE_SHARE_WRITE | FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
    if (h == INVALID_HANDLE_VALUE)
    {
        // handle the error ...
        return 1;
    }

    STARTUPINFO sinfo;      
    ZeroMemory(&sinfo, sizeof(sinfo));
    sinfo.cb = sizeof(sinfo);

    PROCESS_INFORMATION pinfo;
    ZeroMemory(&pinfo, sizeof(pinfo));

    _TCHAR cmd[(MAX_PATH *2) + 10] = {};
    _tsprintf(cmd, _T("\"%s\" \"%s\""), _T("PATH to process 2"), argv[1]);

    if (!CreateProcess(0, cmd, 0, 0, TRUE, NORMAL_PRIORITY_CLASS, 0, 0, &sinfo, &pinfo))
    {
        // handle the error ...
        return 1;
    }

    char c = '1';
    DWORD w;
    WriteFile(h, &c, 1, &w, 0);
    ...

    CloseHandle(h);
    return 0;
}

过程2：

#include <Windows.h>
#include <process.h>
#include <stdio.h>
#include <tchar.h>

int _tmain(int argc, _TCHAR* argv[]) 
{
    if (argc < 2)
    { 
        // ...
        return 1;
    }

    //argv[1] - the name of the file I want to open
    HANDLE h = CreateFile(argv[1], GENERIC_READ | GENERIC_WRITE, FILE_SHARE_WRITE | FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
    if (h == INVALID_HANDLE_VALUE)
    {
        // handle the error ...
        return 1;
    }

    char c = '2';
    DWORD w;
    WriteFile(h, &c, 1, &w, 0);
    ...

    CloseHandle(h);
    return 0;
}

否则，请考虑让进程 1 复制文件句柄，然后让进程 2 继承副本而不是原始文件。