C development

TODO: work in progress

Return values

Most of the API functions return 1 if successful or -1 on error.

The close function is an exception since it returns 0 if successful or -1 on error.

More details about the return values for each API function can be found in libvmdk.h

Examples

The following examples require the following headers to be included:

#include <stdlib.h>
#include <stdio.h>

#include <libvmdk.h>

handle structure

Allocate handle structure

libvmdk_error_t *error = NULL;
libvmdk_handle_t *handle = NULL;

if( libvmdk_handle_initialize(&handle, &error) != 1 )
{
    fprintf(stderr, "Unable to initialize handle.\n");

    libvmdk_error_free(&error);

    exit(EXIT_FAILURE);
}

When calling the libvmdk_handle_initialize function the handle argument must refer to NULL to allocate and initialize a handle structure. The error argument is optional and can be NULL.

The function will return 1 if successful or -1 on error. On error an the library creates an error structure except if error is NULL e.g.

libvmdk_handle_initialize(&handle, NULL);

The error structure must be freed by calling the libvmdk_error_free function.

Free handle structure

if( libvmdk_handle_free(&handle, &error) != 1 )
{
    fprintf(stderr, "Unable to free handle.\n");

    libvmdk_error_free(&error);

    exit(EXIT_FAILURE);
}

The function will return 1 if successful or -1 on error. File is set to NULL. The function will also close the handle if it was opened.

Open handle

filename = "image.vmdk";

if( libvmdk_handle_open(handle, filename, LIBVMDK_OPEN_READ, &error) != 1 )
{
    fprintf(stderr, "Unable to open handle.\n" );

    libvmdk_handle_free(&handle, NULL);
    libvmdk_error_free(&error);

    exit(EXIT_FAILURE);
}

libvmdk provides both narrow and wide character string functions for filenames. The wide character equivalent of the open function is libvmdk_handle_open_wide. By default libvmdk will only enable wide character string support on Windows since other operating systems have build-in support for UTF-8 narrow character strings.

To compile with wide character support add --enable-wide-character-type=yes to configure, e.g.:

./configure --enable-wide-character-type=yes

Or on Windows define WINAPI and either _UNICODE or UNICODE

When wide character string support is enabled LIBVMDK_HAVE_WIDE_CHARACTER_TYPE is defined in <libvmdk/features.h>

Open handle using a file-like object

TODO describe

libvmdk allows to be compiled with file-like object support using libbfio. The libvmdk configure script will automatically detect if a compatible version of libbfio is available.

When libbfio is support is enabled LIBVMDK_HAVE_BFIO is defined in <libvmdk/features.h>

Close handle

if( libvmdk_handle_close(handle, &error) != 0 )
{
    fprintf(stderr, "Unable to close handle.\n" );

    libvmdk_handle_free(&handle, NULL);
    libvmdk_error_free(&error);

    exit(EXIT_FAILURE);
}

Also see

• libvmdk.h
• man 3 libvmdk