{
const size_t alloc_size = 128;
STRSAFE_LPSTR result=(STRSAFE_LPSTR)<\/strong><\/font>CoTaskMemAlloc(alloc_size);
STRSAFE_LPCSTR teststr = "This is return string From Native DLL";
StringCchCopyA ( result, alloc_size, teststr );
return result;
}<\/strong><\/font><\/p>\n
Point of Interest<\/h3>\n\n- STRSAFE_LPSTR<\/strong> is a typedef of char * <\/li>\n
- StringCchCopy<\/strong> is a replacement for strcpy (with safety). The size, in characters, of the destination buffer is provided to the function to ensure that StringCchCopyb does not write past the end of this buffer. has two variants.\n
\n\n- StringCchCopyA<\/strong> (ANSI Version) <\/li>\n
- StringCchCopyW<\/strong> (Unicode\/Wide character Version) <\/li>\n<\/ul>\n
- If you want to use a heap that is shared between native and managed<\/strong>, it is more common to use the COM heap.\n
\n- On the native side use
CoTaskMemAlloc()<\/strong><\/code><\/a> and CoTaskMemFree()<\/strong><\/code><\/a>. <\/li>\n- On the managed side use
Marshal.AllocCoTaskMem()<\/strong><\/code><\/a> and Marshal.FreeCoTaskMem()<\/strong><\/code><\/a>. <\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\nWriting the client code (the managed part) <\/h3>\n
one can simple create a console base application which can use this dll. let\u2019s name it MarshallingTest.<\/strong><\/p>\nsee the code snippet below.<\/p>\n
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;<\/font><\/p>\nnamespace MarshallingTest
{
class Program
{
<\/font>[DllImport("Win32Native.dll")] <\/strong><\/font><\/font>public static extern String GetStringFromDLL();<\/strong><\/font><\/font><\/p>\n static void Main(string[] args)
{
Console.WriteLine("Line displayed below is returned from a Native DLL");
string strData = GetStringFromDLL();
Console.WriteLine ( "Returned value [" + strData +"]" );
}
}
}<\/font><\/p>\nPoint of Interest<\/h3>\n\n- namespace System.Runtime.InteropServices;<\/strong> defines the declarations necessary for Interop operations, like DllImport, <\/li>\n
- DllImport defines the DLL entry point. <\/li>\n<\/ul>\n
compile and execute you will get following output.<\/p>\n
![\"image\"](\"http:\/\/praveenkatiyar.wordpress.com\/wp-content\/uploads\/2013\/07\/image_thumb2.png\" "\\"image\\"")
<\/a><\/p>\n <\/font><\/p>\n","protected":false},"excerpt":{"rendered":"Define a function in native dll (let say it \u201cWin32Native.dll\u201d) as shown below. extern "C" __declspec(dllexport) char * GetStringFromDLL() { const size_t alloc_size = 128; STRSAFE_LPSTR result=(STRSAFE_LPSTR)CoTaskMemAlloc(alloc_size); STRSAFE_LPCSTR teststr = "This is return string From Native DLL"; StringCchCopyA ( result, alloc_size, teststr ); return result; } Point of Interest STRSAFE_LPSTR… Continue reading Interoperability Returning a string from Wn32 DLL<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,9,15],"tags":[],"class_list":["post-44","post","type-post","status-publish","format-standard","hentry","category-codeproject","category-interoperability","category-win32","entry"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/posts\/44","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/comments?post=44"}],"version-history":[{"count":0,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/posts\/44\/revisions"}],"wp:attachment":[{"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/media?parent=44"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/categories?post=44"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/tags?post=44"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- \n
- StringCchCopyA<\/strong> (ANSI Version) <\/li>\n
- StringCchCopyW<\/strong> (Unicode\/Wide character Version) <\/li>\n<\/ul>\n
- If you want to use a heap that is shared between native and managed<\/strong>, it is more common to use the COM heap.\n
- \n
- On the native side use
CoTaskMemAlloc()<\/strong><\/code><\/a> andCoTaskMemFree()<\/strong><\/code><\/a>. <\/li>\n- On the managed side use
Marshal.AllocCoTaskMem()<\/strong><\/code><\/a> andMarshal.FreeCoTaskMem()<\/strong><\/code><\/a>. <\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\nWriting the client code (the managed part) <\/h3>\n
one can simple create a console base application which can use this dll. let\u2019s name it MarshallingTest.<\/strong><\/p>\n
see the code snippet below.<\/p>\n
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;<\/font><\/p>\nnamespace MarshallingTest
{
class Program
{
<\/font>[DllImport("Win32Native.dll")] <\/strong><\/font><\/font>public static extern String GetStringFromDLL();<\/strong><\/font><\/font><\/p>\nstatic void Main(string[] args)
{
Console.WriteLine("Line displayed below is returned from a Native DLL");
string strData = GetStringFromDLL();
Console.WriteLine ( "Returned value [" + strData +"]" );
}
}
}<\/font><\/p>\nPoint of Interest<\/h3>\n
- \n
- namespace System.Runtime.InteropServices;<\/strong> defines the declarations necessary for Interop operations, like DllImport, <\/li>\n
- DllImport defines the DLL entry point. <\/li>\n<\/ul>\n
compile and execute you will get following output.<\/p>\n
<\/a><\/p>\n<\/font><\/p>\n","protected":false},"excerpt":{"rendered":"
Define a function in native dll (let say it \u201cWin32Native.dll\u201d) as shown below. extern "C" __declspec(dllexport) char * GetStringFromDLL() { const size_t alloc_size = 128; STRSAFE_LPSTR result=(STRSAFE_LPSTR)CoTaskMemAlloc(alloc_size); STRSAFE_LPCSTR teststr = "This is return string From Native DLL"; StringCchCopyA ( result, alloc_size, teststr ); return result; } Point of Interest STRSAFE_LPSTR… Continue reading Interoperability Returning a string from Wn32 DLL<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,9,15],"tags":[],"class_list":["post-44","post","type-post","status-publish","format-standard","hentry","category-codeproject","category-interoperability","category-win32","entry"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/posts\/44","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/comments?post=44"}],"version-history":[{"count":0,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/posts\/44\/revisions"}],"wp:attachment":[{"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/media?parent=44"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/categories?post=44"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/praveenkatiyar.in\/blog\/index.php\/wp-json\/wp\/v2\/tags?post=44"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- DllImport defines the DLL entry point. <\/li>\n<\/ul>\n
- On the managed side use
- StringCchCopyW<\/strong> (Unicode\/Wide character Version) <\/li>\n<\/ul>\n
- \n