system call & library functions in unix(APUE study 1)

最新推荐文章于 2025-11-30 14:58:39 发布

原创最新推荐文章于 2025-11-30 14:58:39 发布 · 903 阅读

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#library #system #unix #function #user #interface

本文探讨了系统调用与库函数之间的区别。从实现者的角度来看，这两者有着本质的不同；而从用户的角度来看，这种区别则不那么重要。文章通过具体的例子，如sbrk(2)作为系统调用与malloc作为库函数，解释了它们各自的作用及如何工作。

1 Both system call and library functions are in the form of C functions,for user to invoke. We can consider the system calls as being C functions.
2 From an implementor 's point of view, the distinction between a system call and a library function is fundamental.
3 From a user's perspective, the difference is not as critical.
eg. sbrk(2) is a system call, however,malloc is a library function:the system call in the kernel allocates an additonla chunk of space on behalf of the process. The malloc library function manages this space from user level.
4 Another difference between system calls or library functions is that system calls usually provide a minimal interface,whereas library functions often provide more elaborate functionality.