Parent -and Child without IPC

diff -r 4816d766a08a -r f345bda72bc4 Symbian3/PDK/Source/GUID-209F3620-2361-4AED-9F7A-02E72F9EE8FE.dita --- a/Symbian3/PDK/Source/GUID-209F3620-2361-4AED-9F7A-02E72F9EE8FE.dita Tue Mar 30 11:42:04 2010 +0100 +++ b/Symbian3/PDK/Source/GUID-209F3620-2361-4AED-9F7A-02E72F9EE8FE.dita Tue Mar 30 11:56:28 2010 +0100 @@ -1,81 +1,81 @@ - - - - - -Parent -and Child without IPC -

In this scenario, the parent process creates the child, but there is no -subsequent communication between the two (except maybe the parent waiting -for termination of the child via use of the waitpid() function).

Rather than use the fork()/exec() combination -to achieve this the posix_spawn() API can be used instead. -This API will create a process by a single API call. Additionally, actions -can be performed on inherited file descriptors to change access before the -child's main is called. For more detailed information on the posix_spawn() function -consult the relevant Open Group standard pages available at http:\\www.opengroup.org.

Parent process fork() and exec() functions

The following code shows how the creation of a child process can be implemented -using the fork() and exec() functions. Note -that inclusion of header files has been omitted for clarity.

-int main(int argc, char *argv[]) -{ - pid_t Childpid = fork(); - - if(Childpid == 0) - { - //Running in Child process - - //exec() to replace the child process executable - char execFileName[] = "/root/PortDoc/Example0_c/Posix/child/ChildProg"; - - execl(execFileName,NULL); - } - else - { - //Running in parent process - - //Wait for the child process to terminate - waitpid(Childpid,NULL,0); - - printf("\r\n*** Child process finished ***\r\n"); - - } - - return EXIT_SUCCESS; -} - -

Using the posix_spawn() function

The following code shows how the above can be modified to use the posix_spawn() operation.

-int main(int argc, char *argv[]) -{ - pid_t Childpid; - char execFileName[] = "/root/PortDoc/Example0_c/Symbian/child/ChildProg"; - - int RetVal= posix_spawn(&Childpid,execFileName,NULL,NULL,NULL,NULL); - - (void)waitpid(Childpid,NULL,0); - - printf("\r\n*** Child process finished ***\r\n"); - - return EXIT_SUCCESS; -} - -

Child process example

The child code shown is unaffected by the mechanism used to spawn it, that -is, fork()/exec() or posix_spawn(), -but an example is shown below for completeness.

-int main(void) -{ - printf("\r\n*** Child Running ***\r\n"); - - return EXIT_SUCCESS; -} - + + + + + +Parent +and Child without IPC +

In this scenario, the parent process creates the child, but there is no +subsequent communication between the two (except maybe the parent waiting +for termination of the child via use of the waitpid() function).

Rather than use the fork()/exec() combination +to achieve this the posix_spawn() API can be used instead. +This API will create a process by a single API call. Additionally, actions +can be performed on inherited file descriptors to change access before the +child's main is called. For more detailed information on the posix_spawn() function +consult the relevant Open Group standard pages available at http:\\www.opengroup.org.

Parent process fork() and exec() functions

The following code shows how the creation of a child process can be implemented +using the fork() and exec() functions. Note +that inclusion of header files has been omitted for clarity.

+int main(int argc, char *argv[]) +{ + pid_t Childpid = fork(); + + if(Childpid == 0) + { + //Running in Child process + + //exec() to replace the child process executable + char execFileName[] = "/root/PortDoc/Example0_c/Posix/child/ChildProg"; + + execl(execFileName,NULL); + } + else + { + //Running in parent process + + //Wait for the child process to terminate + waitpid(Childpid,NULL,0); + + printf("\r\n*** Child process finished ***\r\n"); + + } + + return EXIT_SUCCESS; +} + +

Using the posix_spawn() function

The following code shows how the above can be modified to use the posix_spawn() operation.

+int main(int argc, char *argv[]) +{ + pid_t Childpid; + char execFileName[] = "/root/PortDoc/Example0_c/Symbian/child/ChildProg"; + + int RetVal= posix_spawn(&Childpid,execFileName,NULL,NULL,NULL,NULL); + + (void)waitpid(Childpid,NULL,0); + + printf("\r\n*** Child process finished ***\r\n"); + + return EXIT_SUCCESS; +} + +

Child process example

The child code shown is unaffected by the mechanism used to spawn it, that +is, fork()/exec() or posix_spawn(), +but an example is shown below for completeness.

+int main(void) +{ + printf("\r\n*** Child Running ***\r\n"); + + return EXIT_SUCCESS; +} + \ No newline at end of file