Parent Process ID
Every process has an associated parent process ID ( PPID ). The parent process is the process that forked (generated) the child process. The ID of the parent process can be obtained by using the system call getppid (Table 2.2).
Table 2.2. Summary of the getppid System Call.
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Include File(s) |
|
Manual Section |
2 | |
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Summary |
Pid_t getppid( void ); |
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Return |
Success |
Failure |
Sets errno |
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The parent process ID |
1 |
Yes |
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Like the getpid system call, getppid does not require an argument. If it is successful, it will return the PID number of the parent process. The getppid call will fail, returning a value of -1 and setting errno to EPERM (1) if the calling process does not have the proper access permissions.
The following code segment displays the PPID:
cout << "My Parent Process ID is " << getppid( ) << endl;
Unfortunately, there is no system call that allows a parent process to determine the PIDs of all its child processes. If such information is needed, the parent process should save the returned child PID value from the fork system call as each child process is created.