Use memory files as efficient temporary files by specifying the type=memory attribute in fopen() before creating the temporary file. Some applications use temporary files to pass data between program modules.
When using one of the z/OS® UNIX shells, an MVS memory file may or may not make an efficient temporary file. This depends on whether your z/OS UNIX XL C/C++ application program uses fork() and exec() functions to call another program to run in a child process. The child process does not inherit MVS memory files after an exec() function. For more information, see Accessing MVS data sets.