- 1 year ago
WinAPI - How to redirect all stdout of a program and external DLLs to the Win32 standard output handle?
To redirect the standard output (stdout) of a program and external DLLs to the Win32 standard output handle, you can make use of the WinAPI functions SetStdHandle
and CreateFile
.
Here's an example of how you can redirect the stdout to the Win32 standard output handle:
cpp#include <windows.h>
#include <iostream>
int main()
{
// Create a handle to the Win32 standard output
HANDLE hStdout = GetStdHandle(STD_OUTPUT_HANDLE);
// Open the console output and assign it to the standard output handle
HANDLE hConsoleOut = CreateFile("CONOUT$", GENERIC_WRITE, FILE_SHARE_WRITE, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
SetStdHandle(STD_OUTPUT_HANDLE, hConsoleOut);
// Redirect the stdout to the Win32 standard output handle
std::cout.rdbuf(reinterpret_cast<std::streambuf*>(hConsoleOut));
// Test the redirection by printing a message
std::cout << "Hello, Win32 standard output!" << std::endl;
// Restore the original standard output handle
SetStdHandle(STD_OUTPUT_HANDLE, hStdout);
// Close the console output handle
CloseHandle(hConsoleOut);
return 0;
}
In this example, we first obtain a handle to the Win32 standard output using GetStdHandle(STD_OUTPUT_HANDLE)
. Then, we open the console output using CreateFile
with "CONOUT$"
as the filename. Next, we assign the console output handle to the standard output handle using SetStdHandle(STD_OUTPUT_HANDLE, hConsoleOut)
. Finally, we redirect the stdout stream to the Win32 standard output handle using std::cout.rdbuf()
.
After the redirection, any output sent to std::cout
will be directed to the Win32 standard output handle. You can replace the std::cout
with other output streams like std::cerr
or std::clog
if needed.
Remember to restore the original standard output handle using SetStdHandle
and close the console output handle using CloseHandle
to clean up.
Note that this code assumes that you have a console window associated with the process. If your program is a GUI application without a console window, you may need to allocate a console using AllocConsole
before redirecting the output.
Please note that modifying the standard output handle can have unintended side effects, so use this approach with caution.