Hi, I'm trying to overwrite the weak symbol mpi_waitany_ (fortran symbol), but I get an error (the function doesn't seem to work since it returns an index of 0). Here is my code, any idea why it doesn't work? void mpi_waitany_(MPI_Fint* count, MPI_Fint* array_of_requests, MPI_Fint* index, MPI_Fint* status, MPI_Fint* err) { MPI_Status cstatus; MPI_Status_f2c(status, &cstatus); MPI_Request* c_req = (MPI_Request*)malloc(sizeof(MPI_Request)*(*count)); int i; for(i=0;i<*count;i++) { c_req[i] = MPI_Request_f2c(array_of_requests[i]); } *err = PMPI_Waitany(*count,c_req,index,&cstatus); MPI_Status_c2f(&cstatus, status); for(i=0;i<*count;i++) { array_of_requests[i] = MPI_Request_c2f(c_req[i]); } free(c_req); } Thanks! Matthieu Dorier PhD student at ENS Rennes http://people.irisa.fr/Matthieu.Dorier