#include <modkit/iap.h>10 functions · 3 structs · 2 enums · 9 typedefs
In-App Purchases - Cross-platform monetization API.
Provides a unified interface for in-app purchases across:iOS (StoreKit 2)Android (Google Play Billing Library)Steam (Steamworks ISteamMicroTxn - requires backend server)Web/Custom (extensible for Stripe, PayPal, etc.) Basic usage:
mk_iap_consumefunctionvoid mk_iap_consume(const char *product_id)Consume a consumable product.
Must be called after granting the content for consumable products. This allows the product to be purchased again.
| Parameter | Type | Description |
|---|---|---|
product_id | const char * | Product identifier to consume |
mk_iap_fetch_productsfunctionvoid mk_iap_fetch_products(const char **product_ids, int count, mk_iap_products_fn callback, void *user_data)Fetch product information from the store.
Product IDs should match those configured in App Store Connect, Google Play Console, or Steamworks.
| Parameter | Type | Description |
|---|---|---|
product_ids | const char ** | Array of product identifiers to fetch |
count | int | Number of product IDs |
callback | mk_iap_products_fn | Called when fetch completes (required) |
user_data | void * | User pointer passed to callback |
mk_iap_get_backend_namefunctionconst char * mk_iap_get_backend_name(void)Get the current IAP backend name.
Returns Backend identifier ("ios", "android", "steam", "web", "stub")
mk_iap_initfunctionbool mk_iap_init(void)Initialize the IAP system.
Must be called before any other IAP functions. On iOS/Android, this connects to the app store.
Returns true if initialization succeeded (or IAP is available)
mk_iap_is_availablefunctionbool mk_iap_is_available(void)Check if in-app purchases are available.
May return false if:Parental controls block purchasesUser is not signed into an accountPlatform doesn't support IAPmk_iap_init() was not called
Returns true if purchases can be made
mk_iap_pollfunctionvoid mk_iap_poll(void)Process pending IAP operations.
Call this every frame to process callbacks from async operations. If using mk_app_run(), this is called automatically.
mk_iap_purchasefunctionvoid mk_iap_purchase(const char *product_id, mk_iap_purchase_fn callback, void *user_data)Initiate a purchase.
Opens the platform's purchase UI. The callback is called when the purchase completes, fails, or is cancelled by the user.
| Parameter | Type | Description |
|---|---|---|
product_id | const char * | Product identifier to purchase |
callback | mk_iap_purchase_fn | Called when purchase completes (required) |
user_data | void * | User pointer passed to callback |
mk_iap_restore_purchasesfunctionvoid mk_iap_restore_purchases(mk_iap_restore_fn callback, void *user_data)Restore previous non-consumable and subscription purchases.
Used when users reinstall the app or switch devices. Only restores MK_IAP_NON_CONSUMABLE and MK_IAP_SUBSCRIPTION products.
| Parameter | Type | Description |
|---|---|---|
callback | mk_iap_restore_fn | Called when restore completes (required) |
user_data | void * | User pointer passed to callback |
mk_iap_shutdownfunctionvoid mk_iap_shutdown(void)Shutdown the IAP system.
Releases all resources. Any pending operations are cancelled.
mk_iap_web_configurefunctionvoid mk_iap_web_configure(const mk_iap_web_config_t *config)Configure the web/custom payment backend.
| Parameter | Type | Description |
|---|---|---|
config | const mk_iap_web_config_t * | Web configuration |
mk_iap_productstructProduct information returned from the store.
All string pointers are valid until the next mk_iap_fetch_products() call or mk_iap_shutdown().
| Field | Type | Description |
|---|---|---|
id | const char * | Product identifier (SKU). |
title | const char * | Localized product title. |
description | const char * | Localized product description. |
price | const char * | Formatted localized price (e.g., "$4.99"). |
currency_code | const char * | ISO 4217 currency code (e.g., "USD"). |
price_value | float | Numeric price in local currency. |
type | mk_iap_product_type_t | Product type. |
subscription | struct mk_iap_product::@310202220177241003145166305152321324312356322162 | The subscription. |
subscription.period | mk_iap_subscription_period_t | The period. |
subscription.intro_price | const char * | Introductory offer price (NULL if none). |
subscription.intro_period_days | int | Intro offer duration in days (0 if none). |
subscription.has_free_trial | bool | True if free trial is available. |
subscription.free_trial_days | int | Free trial duration in days. |
mk_iap_receiptstructPurchase receipt/transaction information.
Contains platform-specific receipt data for server-side validation. String pointers are valid until the callback returns.
| Field | Type | Description |
|---|---|---|
product_id | const char * | Product identifier that was purchased. |
transaction_id | const char * | Unique transaction ID from the store. |
receipt_data | const char * | Platform-specific receipt for validation. |
purchase_time | uint64_t | Unix timestamp (seconds since epoch). |
needs_consume | bool | True if this is a consumable needing consume(). |
platform | union mk_iap_receipt::@123051041370116350164142276237202274157364377073 | The platform. |
platform.android.order_id | const char * | Google Play order ID. |
platform.android.purchase_token | const char * | Token for server verification. |
platform.android.purchase_state | int | 0=Purchased, 1=Pending, 2=Cancelled |
platform.ios.app_account_token | const char * | Optional UUID linking to your user. |
platform.ios.environment | const char * | "Production" or "Sandbox" |
platform.steam.steam_id | uint64_t | Purchaser's Steam ID. |
platform.steam.order_id | uint64_t | Steam order ID. |
platform.ios | struct mk_iap_receipt::@123051041370116350164142276237202274157364377073::@250212055016146206172342010127166272273147140034 | The ios. |
platform.android | struct mk_iap_receipt::@123051041370116350164142276237202274157364377073::@343311167355265025332326200240164021042263147320 | The android. |
platform.steam | struct mk_iap_receipt::@123051041370116350164142276237202274157364377073::@223354340154320131303372041360050146242211062254 | The steam. |
mk_iap_web_configstructWeb/custom backend configuration.
For web builds or when integrating custom payment processors (Stripe, PayPal, etc.), configure the checkout flow here.
| Field | Type | Description |
|---|---|---|
checkout_url | const char * | Base URL for checkout (e.g., "https://your-server.com/checkout"). |
on_result | mk_iap_web_result_fn | Called when payment window returns a result. |
user_data | void * | User context. |
mk_iap_product_typeenumProduct type classification.
| Value | Description |
|---|---|
MK_IAP_CONSUMABLE | One-time use (coins, gems, lives). |
MK_IAP_NON_CONSUMABLE | Permanent unlock (remove ads, levels). |
MK_IAP_SUBSCRIPTION | Recurring payment (premium access). |
mk_iap_subscription_periodenumSubscription period (for MK_IAP_SUBSCRIPTION products).
| Value | Description |
|---|---|
MK_IAP_PERIOD_UNKNOWN | Selects unknown. |
MK_IAP_PERIOD_WEEKLY | Selects weekly. |
MK_IAP_PERIOD_MONTHLY | Selects monthly. |
MK_IAP_PERIOD_QUARTERLY | 3 months |
MK_IAP_PERIOD_BIANNUAL | 6 months |
MK_IAP_PERIOD_ANNUAL | 12 months |
mk_iap_product_ttypedeftypedef struct mk_iap_product mk_iap_product_tProduct information returned from the store.
All string pointers are valid until the next mk_iap_fetch_products() call or mk_iap_shutdown().
mk_iap_product_type_ttypedeftypedef enum mk_iap_product_type mk_iap_product_type_tProduct type classification.
mk_iap_products_fntypedeftypedef void(*) mk_iap_products_fn(const mk_iap_product_t *products, int count, const char *error, void *user_data)Callback for product information fetch completion.
mk_iap_purchase_fntypedeftypedef void(*) mk_iap_purchase_fn(const mk_iap_receipt_t *receipt, const char *error, void *user_data)Callback for purchase completion.
mk_iap_receipt_ttypedeftypedef struct mk_iap_receipt mk_iap_receipt_tPurchase receipt/transaction information.
Contains platform-specific receipt data for server-side validation. String pointers are valid until the callback returns.
mk_iap_restore_fntypedeftypedef void(*) mk_iap_restore_fn(const mk_iap_receipt_t *receipts, int count, const char *error, void *user_data)Callback for restore purchases completion.
mk_iap_subscription_period_ttypedeftypedef enum mk_iap_subscription_period mk_iap_subscription_period_tSubscription period (for MK_IAP_SUBSCRIPTION products).
mk_iap_web_config_ttypedeftypedef struct mk_iap_web_config mk_iap_web_config_tWeb/custom backend configuration.
For web builds or when integrating custom payment processors (Stripe, PayPal, etc.), configure the checkout flow here.
mk_iap_web_result_fntypedeftypedef void(*) mk_iap_web_result_fn(bool success, const char *receipt, void *user_data)Custom payment result callback for web backends.