Contents
What is exec operating system?
In computing, exec is a functionality of an operating system that runs an executable file in the context of an already existing process, replacing the previous executable. In OS command interpreters, the exec built-in command replaces the shell process with the specified program.
What type of call is a system () call?
A system call is a way for programs to interact with the operating system. A computer program makes a system call when it makes a request to the operating system’s kernel. System call provides the services of the operating system to the user programs via Application Program Interface(API).
What does exec system call do in Linux?
Linux Exec System Call. The exec system call is used to execute a file which is residing in an active process. When exec is called the previous executable file is replaced and new file is executed. More precisely, we can say that using exec system call will replace the old file or program from the process with a new file or program.
How is fork system call different from exec system call?
The fork () system call is used to create an exact copy of a running process and the created copy is the child process and the running process is the parent process. Whereas, exec () system call is used to replace a process image with a new process image. Hence there is no concept of parent and child processes in exec () system call.
How is the PID of an exec system call changed?
PID of the process is not changed but the data, code, stack, heap, etc. of the process are changed and are replaced with those of newly loaded process. The new process is executed from the entry point. Exec system call is a collection of functions and in C programming language, the standard names for these functions are as follows:
How does exec system call replace a file?
More precisely, we can say that using exec system call will replace the old file or program from the process with a new file or program. The entire content of the process is replaced with a new program.