<p>You can annotate allocations with your own information, e.g. for debugging purposes. To do that, fill <aclass="el"href="struct_vma_allocation_create_info.html#a8259e85c272683434f4abb4ddddffe19"title="Custom general-purpose pointer that will be stored in VmaAllocation, can be read as VmaAllocationInfo...">VmaAllocationCreateInfo::pUserData</a> field when creating an allocation. It is an opaque <code>void*</code> pointer. You can use it e.g. as a pointer, some handle, index, key, ordinal number or any other value that would associate the allocation with your custom metadata.</p>
<divclass="ttc"id="astruct_vma_allocation_create_info_html_a8259e85c272683434f4abb4ddddffe19"><divclass="ttname"><ahref="struct_vma_allocation_create_info.html#a8259e85c272683434f4abb4ddddffe19">VmaAllocationCreateInfo::pUserData</a></div><divclass="ttdeci">void * pUserData</div><divclass="ttdoc">Custom general-purpose pointer that will be stored in VmaAllocation, can be read as VmaAllocationInfo...</div><divclass="ttdef"><b>Definition:</b> vk_mem_alloc.h:1251</div></div>
<divclass="ttc"id="astruct_vma_allocation_create_info_html_accb8b06b1f677d858cb9af20705fa910"><divclass="ttname"><ahref="struct_vma_allocation_create_info.html#accb8b06b1f677d858cb9af20705fa910">VmaAllocationCreateInfo::usage</a></div><divclass="ttdeci">VmaMemoryUsage usage</div><divclass="ttdoc">Intended usage of memory.</div><divclass="ttdef"><b>Definition:</b> vk_mem_alloc.h:1220</div></div>
<divclass="ttc"id="astruct_vma_allocation_html"><divclass="ttname"><ahref="struct_vma_allocation.html">VmaAllocation</a></div><divclass="ttdoc">Represents single memory allocation.</div></div>
</div><!-- fragment --><p>The pointer may be later retrieved as <aclass="el"href="struct_vma_allocation_info.html#adc507656149c04de7ed95d0042ba2a13"title="Custom general-purpose pointer that was passed as VmaAllocationCreateInfo::pUserData or set using vma...">VmaAllocationInfo::pUserData</a>:</p>
<divclass="ttc"id="agroup__group__alloc_html_ga86dd08aba8633bfa4ad0df2e76481d8b"><divclass="ttname"><ahref="group__group__alloc.html#ga86dd08aba8633bfa4ad0df2e76481d8b">vmaGetAllocationInfo</a></div><divclass="ttdeci">void vmaGetAllocationInfo(VmaAllocator allocator, VmaAllocation allocation, VmaAllocationInfo *pAllocationInfo)</div><divclass="ttdoc">Returns current information about specified allocation.</div></div>
<divclass="ttc"id="astruct_vma_allocation_info_html"><divclass="ttname"><ahref="struct_vma_allocation_info.html">VmaAllocationInfo</a></div><divclass="ttdoc">Parameters of VmaAllocation objects, that can be retrieved using function vmaGetAllocationInfo().</div><divclass="ttdef"><b>Definition:</b> vk_mem_alloc.h:1327</div></div>
<divclass="ttc"id="astruct_vma_allocation_info_html_adc507656149c04de7ed95d0042ba2a13"><divclass="ttname"><ahref="struct_vma_allocation_info.html#adc507656149c04de7ed95d0042ba2a13">VmaAllocationInfo::pUserData</a></div><divclass="ttdeci">void * pUserData</div><divclass="ttdoc">Custom general-purpose pointer that was passed as VmaAllocationCreateInfo::pUserData or set using vma...</div><divclass="ttdef"><b>Definition:</b> vk_mem_alloc.h:1374</div></div>
</div><!-- fragment --><p>It can also be changed using function <aclass="el"href="group__group__alloc.html#gaf9147d31ffc11d62fc187bde283ed14f"title="Sets pUserData in given allocation to new value.">vmaSetAllocationUserData()</a>.</p>
<p>Values of (non-zero) allocations' <code>pUserData</code> are printed in JSON report created by <aclass="el"href="group__group__stats.html#gaa4fee7eb5253377599ef4fd38c93c2a0"title="Builds and returns statistics as a null-terminated string in JSON format.">vmaBuildStatsString()</a> in hexadecimal form.</p>
<p>There is alternative mode available where <code>pUserData</code> pointer is used to point to a null-terminated string, giving a name to the allocation. To use this mode, set <aclass="el"href="group__group__alloc.html#ggad9889c10c798b040d59c92f257cae597aa6f24f821cd6a7c5e4a443f7bf59c520">VMA_ALLOCATION_CREATE_USER_DATA_COPY_STRING_BIT</a> flag in <aclass="el"href="struct_vma_allocation_create_info.html#add09658ac14fe290ace25470ddd6d41b"title="Use VmaAllocationCreateFlagBits enum.">VmaAllocationCreateInfo::flags</a>. Then <code>pUserData</code> passed as <aclass="el"href="struct_vma_allocation_create_info.html#a8259e85c272683434f4abb4ddddffe19"title="Custom general-purpose pointer that will be stored in VmaAllocation, can be read as VmaAllocationInfo...">VmaAllocationCreateInfo::pUserData</a> or argument to <aclass="el"href="group__group__alloc.html#gaf9147d31ffc11d62fc187bde283ed14f"title="Sets pUserData in given allocation to new value.">vmaSetAllocationUserData()</a> must be either null or a pointer to a null-terminated string. The library creates internal copy of the string, so the pointer you pass doesn't need to be valid for whole lifetime of the allocation. You can free it after the call.</p>
</div><!-- fragment --><p>The value of <code>pUserData</code> pointer of the allocation will be different than the one you passed when setting allocation's name - pointing to a buffer managed internally that holds copy of the string.</p>
</div><!-- fragment --><p>That string is also printed in JSON report created by <aclass="el"href="group__group__stats.html#gaa4fee7eb5253377599ef4fd38c93c2a0"title="Builds and returns statistics as a null-terminated string in JSON format.">vmaBuildStatsString()</a>.</p>
<dlclass="section note"><dt>Note</dt><dd>Passing string name to VMA allocation doesn't automatically set it to the Vulkan buffer or image created with it. You must do it manually using an extension like VK_EXT_debug_utils, which is independent of this library. </dd></dl>
