/tmp/ja664344> LD_LIBRARY_PATH=$PWD:$LD_LIBRARY_PATH /home/ja664344/software/mpich/4.0.2/linux/gcc/11.2.0/bin/mpiexec -prepend-rank -n 2 ./session_driver
[0] Hello from session rank 0
[0] Hello from app rank 0
[0] lib internal ret = 0
[0] Closing lib
[1] Hello from session rank 1
[1] Hello from app rank 1
[1] lib internal ret = 0
[1] Closing lib
[0] lib ret = 0
[1] lib ret = 0

Ich habe auch nochmal geschaut, und das Beispiel aus dem MPI Standard benutzt. Da funktioniert es soweit die Session vor dem MPI_Init zu starten und danach zu schließen. Hier die [session_lib.c](/uploads/-/system/personal_snippet/248/613e21cc8946507d3642d79108649a30/session_lib.c) und der [session_driver.c](/uploads/-/system/personal_snippet/248/1159dd2979dfb4a55a7e3dc89601da95/session_driver.c). Beispiel Output mit mpich 4 ``` /tmp/ja664344> LD_LIBRARY_PATH=$PWD:$LD_LIBRARY_PATH /home/ja664344/software/mpich/4.0.2/linux/gcc/11.2.0/bin/mpiexec -prepend-rank -n 2 ./session_driver [0] Hello from session rank 0 [0] Hello from app rank 0 [0] lib internal ret = 0 [0] Closing lib [1] Hello from session rank 1 [1] Hello from app rank 1 [1] lib internal ret = 0 [1] Closing lib [0] lib ret = 0 [1] lib ret = 0 ``` (Edit: Mit OpenMPI 5.0.0rc10 funktioniert's auch)