What is Wifexited status?

WIFEXITED and WEXITSTATUS are two of the options which can be used to know the exit status of the child. WIFEXITED(status) : returns true if the child terminated normally. WEXITSTATUS(status) : returns the exit status of the child. This macro should be employed only if WIFEXITED returned true.

What is Wnohang?

WNOHANG. This flag specifies that waitpid should return immediately instead of waiting, if there is no child process ready to be noticed. WUNTRACED. This flag specifies that waitpid should report the status of any child processes that have been stopped as well as those that have terminated.

Is stat a Syscall?

Stat system call is a system call in Linux to check the status of a file such as to check when the file was accessed. The stat() system call actually returns file attributes. The file attributes of an inode are basically returned by Stat() function.

What is the zombie state of a process?

A zombie process is a process in its terminated state. This usually happens in a program that has parent-child functions. After a child function has finished execution, it sends an exit status to its parent function.

What is Wifstopped?

WIFSTOPPED, WIFSIGNALED, WIFEXITED, are macros that take an argument status , of type int, as returned by wait() , or wait3() , or wait4() . WIFSTOPPED evaluates to true (1) when the process for which the wait() call was made is stopped, or to false (0) otherwise.

What is Wifsignaled?

WIFSIGNALED–Query status to see if a child process ended abnormally. This macro queries the child termination status provided by the wait and waitpid functions. It determines if the child process exited because it raised a signal that caused it to exit.

What is Wexitstatus?

This macro queries the child termination status provided by the wait and waitpid functions. If the WIFEXITED macro indicates that the child process exited normally, the WEXITSTATUS macro returns the exit code specified by the child process.

What is Waitpid?

The waitpid() system call suspends execution of the current process until a child specified by pid argument has changed state. By default, waitpid() waits only for terminated children, but this behaviour is modifiable via the options argument, as described below.

What is an Lstat?

The lstat() function gets status information about a specified file and places it in the area of memory pointed to by buf. If the named file is a symbolic link, lstat() returns information about the symbolic link itself.

What is Lseek?

The lseek() function allows the file offset to be set beyond the end of the file (but this does not change the size of the file). If data is later written at this point, subsequent reads of the data in the gap (a “hole”) return null bytes (‘\0’) until data is actually written into the gap.