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L_ReadFileCommentMemory

Summary

Gets a comment field from a file in memory.

Syntax

#include "l_bitmap.h"

L_LTFIL_API L_INT L_ReadFileCommentMemory(pBuffer, uType, pComment, uLength, nBufferSize, pLoadOptions)

Parameters

L_UCHAR* pBuffer

Pointer to the file in memory.

L_UINT uType

The type of comment. Refer to Types of File Comments.

L_UCHAR* pComment

Pointer to your buffer that will hold the comment field, including the terminating NULL. You can pass NULL if you only want to get the length of the field (the return value).

L_UINT uLength

The size of your buffer that will hold the comment field.

L_SSIZE_T nBufferSize

Size of the file in memory (in bytes).

pLOADFILEOPTION pLoadOptions

Pointer to optional extended load options. Pass NULL to use the default load options.

Returns

Value	Meaning
>=0	Length of the comment field.
< 0	An error occurred. An error occurred. Refer to Return Codes.

Comments

Some file formats can contain comments, and some cannot, and each file format has its own set of comment types. When you save a file, the comments, which LEADTOOLS maintains in a global array, are saved in the file. The index into the array (specified using a constant) determines the type of comment, as described in Types of File Comments.

Before saving a file, you use the L_SetComment function to specify the comments to be saved.

The L_ReadFileCommentMemory function lets you read comments that are already saved in a file in memory. For more information refer to the L_SetComment function.

Notes:

More options are available in the LOADFILEOPTION.
This function does not support Kodak FlashPix files.

Required DLLs and Libraries

LTFIL
File format DLLs
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64, Linux.

Example

This example gets the CMNT_SZDATETIME comment from a TIFF file in memory

L_INT ReadFileCommentMemoryExample(L_UCHAR * pBuf, L_SIZE_T lFileSize) 
{ 
   L_INT nRet; 
   L_CHAR szMessage[80];  /* MessageBox string                */ 
   L_CHAR * pTextToGet;    /* Comment string that we will get  */ 
   HGLOBAL hTextToGet;     /* Handle for memory management     */ 
   L_INT CommentLength;    /* Length of the comment string that we will get */ 
 
   /* Use the return value to get the length of a comment in the file */ 
   CommentLength = L_ReadFileCommentMemory (pBuf, CMNT_SZARTIST, NULL, 0, lFileSize, NULL); 
 
   /* Allocate and lock a zero-filled buffer for the comment */ 
   hTextToGet = GlobalAlloc(GPTR, CommentLength); 
   pTextToGet = (L_CHAR *)GlobalLock( hTextToGet ); 
 
   /* Get the actual comment from the file */ 
   nRet = L_ReadFileCommentMemory (pBuf, CMNT_SZARTIST, (L_UCHAR *) pTextToGet, CommentLength, lFileSize, NULL); 
 
   /* Show the comment that was saved in the file */ 
   sprintf_s(szMessage, ("CMNT_SZARTIST:\n %s"), pTextToGet); 
   MessageBoxA(NULL, szMessage, ("CMNT_SZARTIST"), MB_OK); 
 
   /* Free memory */ 
   GlobalUnlock(hTextToGet); 
   GlobalFree(hTextToGet); 
   return SUCCESS; 
}