1 /* 2 * Copyright (c) 2019 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 29 #ifndef __OS_PROC__ 30 #define __OS_PROC__ 31 32 #include <stddef.h> 33 #include <sys/cdefs.h> 34 #include <os/availability.h> 35 36 /*! 37 * @header 38 * 39 * @preprocinfo 40 * This is for functions that operate on the calling process alone. 41 */ 42 43 __BEGIN_DECLS 44 45 /*! 46 * @function os_proc_available_memory 47 * 48 * @abstract 49 * Return the number of bytes remaining, at the time of the call, before the 50 * current process will hit its current dirty memory limit. 51 * 52 * @discussion 53 * Developers can query this value efficiently whenever it is needed. The return 54 * value is only a snapshot at the time of the call. Caching the result is not 55 * advised. The result may be instantaneously invalidated by actions taken in 56 * another thread or another framework. 57 * 58 * Memory limits can change during the app life cycle. Make sure to check accordingly. 59 * 60 * The size returned is not representative of the total memory of the device, it 61 * is the current dirty memory limit minus the dirty memory footprint used at the 62 * time of the query. 63 * 64 * This interface allows an app to efficiently consume all available memory resources. 65 * Significant memory use, even under the current memory limit, may still cause 66 * system-wide performance including the termination of other apps and system 67 * processes. Take care to use the minimum amount of memory needed to satisfy the 68 * user’s need. 69 * 70 * If you need more information than just the available memory, you can use task_info(). 71 * The information returned is equivalent to the task_vm_info.limit_bytes_remaining 72 * field. task_info() is a more expensive call, and will return information such 73 * as your phys_footprint, which is used to calculate the return of this function. 74 * 75 * Dirty memory contains data that must be kept in RAM (or the equivalent) even 76 * when unused. It is memory that has been modified. 77 * 78 * @param none 79 * 80 * @result 81 * The remaining bytes. 0 is returned if the calling process is not an app, or 82 * the calling process exceeds its memory limit. 83 */ 84 85 API_UNAVAILABLE(macos) API_AVAILABLE(ios(13.0), tvos(13.0), watchos(6.0), bridgeos(4.0)) 86 extern 87 size_t os_proc_available_memory(void); 88 89 __END_DECLS 90 91 #endif 92