Runtime environment, environment variables on Unix and Linux systems

The environment variables listed in the table on "Runtime environment, linking, starting" must be set in order to operate CPI-C applications:

You can set the environment variables as follows:

UPICPATH=directory
UPICTRACE=option
UPICLOG=directory
UPICFILE=name-side-information-file
export UPICPATH UPICTRACE UPICLOG UPICFILE

Resources of a CPI-C program

• A file descriptor is always required for the trace file.

• If data is written to the log file, a file descriptor is only required while the data is being written.

• To read from the upicfile, a file descriptor is only required during the Enable_UTM_UPIC call.

• Transport system resources are also required.

Signals

Signal handling routines in a CPI-C program are allowed for the signals SIGHUP, SIGINT and SIGQUIT. The CPI-C library functions are not interrupted by these three signals. This signal handling does not become effective until the current CPI-C function has terminated.

All other signals are prohibited!