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Application Programming Interface (API) is a set of functions, objects, protocols or datastructures for the support of application development for developers/programmers. It is actually a kind of function definition which specifies how to make available of a specific service of the system/OS. The API's are available from library or from Operating system itself. Whenever a programmer need a specific service from OS, he/she can use appropriate API to do that.
Processes in a system are run in different modes, process run in user mode have no access to the privileged instructions. If they want perform any privileged instructions or need of any services they request kernal for that service through System Calls. System calls are made by way of software interrupt. This is actually a request for the service whereas API is a function description that can be used by the programmer for his programs, its like a tool used to obtain a specific task in his programs.
A system call is generally made by an application programme to the operating system.this instruction interrupts the current executing programme and transfers control to the interrupt routine.The contents of the executing programme are saved.After the interrupt routine finishes its function,control is transferred back to the executing programme.
What else can I help you with?
What are API calls used for?
"API calls" have no specific question; the term APIsimply means application programming interface, and to call an API simply means to invoke a function (or subroutine) from a computer program.Each API call is different in how it is called (e.g. does it require any parameters, and of so, which), when (e.g. can it be called at any time and under all circumstances), what it does and what it returns to the caller.API functions serving closely related purposes are often grouped together into an API.Take this hypothetical example: One API provides services for rounding numbers: one function of this API rounds numbers to the nearest whole number, another function that belongs to the same API rounds numbers to the nearest hundredth.The purpose of API is unlimited. Examples of API include API to allocate, manage and return memory from a heap, API to create, manage and delete files and folders on a hard disk, API to get and set the current time, API to draw lines and other geometric shapes, etc, etc.
Why do you prefer using API over system call to execute services or routines of operating system?
simplicity & portability, especially if POSIX API is used as many totally different OSs support this API. using native OS calls would result in nonportable code.
What is the difference between API 600 and API 602 valves?
The main difference between API 600 and API 503 valves is their port diameter. Also, the pressure testing between the two is different as well.
What is difference between API 6D and API 598?
The pressure test for API 598 is slightly less pressure and less duration than API 6D. API 6D is specifically for pipeline valves.
What is the difference between api 6a and api 610 spec?
Hi, Both are API Standards,which define the specification about wellhead is 6A. and which is define the specification about centrifugal pump is 610. Refer API STANDARD. All the best.
What is the difference between API 6FA and API 607?
Both deal with valves. API6FA is for API 6A and 6D. API607 applies to soft-seated, quarter-turn valves.
Why you use API rather than System Calls?
System calls are much slower than APIs (library calls) since for each system call, a context switch has to occur to load the OS (which then serves the system call).
Applications call on the OS to access hardware or other software by using a call?
API
List all system call interface?
The system call interface defines all the services of the operating system to the programs. The basis of the different variants of the UNIX operating system is different system call interface. SVID (System V interface definitions ) POSIX standard (IEEE) POSIX 1003.4 is API (Application Program Interface) for the real time systems. www.etherlook.com
What is developing a system?
Im pretty sure that is an API.
What is the difference between ISO 9001 and APIQ1?
API Q1 is the quality management system of American petroleum industry. API Q1 IS ISO 9001+ADDITOINAL REQUIREMENTS OF PETROLEUM INDUSTRY. In API Q1 all clauses given in rectangle or in the border are same as ISO 9001 and clauses given outside the borders are the additional requirements of petroleum industry.
What is the difference between API and ASME?
ASME stands for American Society of Mechanical EngineersASTM stands for American Society for Testing and Materials
