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POSIX in C

POSIX in C

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Udeme Harrison
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2 min read

POSIX in C refers to a set of rules and standards that define how programs can interact with an operating system in a consistent and portable way. It ensures that programs written in the C programming language can run on different operating systems without requiring major modifications.

POSIX, which stands for Portable Operating System Interface, is a set of standardized APIs (Application Programming Interfaces) and interface specifications for operating systems. For C programmers, POSIX provides a set of functions, data types, and constants that they can use in their programs. These functions allow them to perform common tasks like working with files, managing processes, communicating between different parts of a program, handling signals, and managing threads.

By following the POSIX standards, programmers can write their code in a way that is compatible with any POSIX-compliant operating system. This means their programs can be easily ported and run on different systems without needing extensive modifications.

To use POSIX functionality, programmers include specific header files in their C programs, which provide access to the POSIX functions, data types, and constants related to the desired functionality. Example of header files that enable POSIX are unistd.h and fcntl.h .

Here are some key areas covered by POSIX in C:

  1. File operations: POSIX provides functions like open, read, write, close, lseek, and file-related data types and constants for file I/O operations.

  2. Process management: POSIX includes functions like fork, exec, wait, exit, and process-related data types and constants for managing processes.

  3. Interprocess communication: POSIX defines APIs for interprocess communication using mechanisms like pipes, message queues, shared memory, and semaphores.

  4. Signal handling: POSIX specifies functions and mechanisms for handling signals, including functions like signal, sigaction, and signal-related constants.

  5. Threads: POSIX provides support for creating and managing threads using functions like pthread_create, pthread_join, pthread_mutex, and more.

While POSIX provides a standardized set of functionality, the specific behaviour and features of POSIX functions may still vary slightly across different operating systems, even if they are POSIX-compliant.