Marshal::StringToHGlobalAnsi Method (String^)

 
System_CAPS_noteNote

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Copies the contents of a managed String into unmanaged memory, converting into ANSI format as it copies.

Namespace:   System.Runtime.InteropServices
Assembly:  mscorlib (in mscorlib.dll)

public:
[SecurityCriticalAttribute]
static IntPtr StringToHGlobalAnsi(
	String^ s
)

Parameters

s
Type: System::String^

A managed string to be copied.

Return Value

Type: System::IntPtr

The address, in unmanaged memory, to where s was copied, or 0 if s is null.

Exception Condition
OutOfMemoryException

There is insufficient memory available.

ArgumentOutOfRangeException

The s parameter exceeds the maximum length allowed by the operating system.

StringToHGlobalAnsi is useful for custom marshaling or when mixing managed and unmanaged code. Because this method allocates the unmanaged memory required for a string, always free the memory by calling FreeHGlobal. StringToHGlobalAnsi provides the opposite functionality of Marshal::PtrToStringAnsi.

This method copies embedded null characters, and includes a terminating null character.

The following example demonstrates how to convert the contents of a managed String class to unmanaged memory and then dispose of the unmanaged memory when done.

using namespace System;
using namespace System::Runtime::InteropServices;

#include <iostream>                                                 // for printf


int main()
{
    // Create a managed string.
    String^ managedString = "Hello unmanaged world (from the managed world).";

    // Marshal the managed string to unmanaged memory.
    char* stringPointer = (char*) Marshal::StringToHGlobalAnsi(managedString ).ToPointer();

    printf("stringPointer = %s\n", stringPointer);

    // Always free the unmanaged string.
    Marshal::FreeHGlobal(IntPtr(stringPointer));

    return 0;
}

SecurityCriticalAttribute

requires full trust for the immediate caller. This member cannot be used by partially trusted or transparent code.

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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