IBM Power Systems 775 Manual page 129

You use the following suffixes to indicate the size in bytes. If you do not use the suffixes, the
size is specified by byte. For example, XLPGASOPTS=stacksize=200_000 specifies that the
space allocated to the stack used by a thread is at least 200,000 bytes:
kb (1 kb represents 1024 bytes)
mb (1 mb represents 1024 kb)
gb (1 gb represents 1024 mb)
tb (1 tb represents 1024 gb)
The suffixes are not case-sensitive. The letter b is optional and is omitted in the suffixes. For
example, XLPGASOPTS=STACKSIZE=10Mb is equivalent to
XLPGASOPTS=stacksize=10m.
You also use the suffixes percent and % to indicate a percentage. For example, the following
commands have the same effect:
XLPGASOPTS=stackcheck=20
XLPGASOPTS=stackcheck=20%
XLPGASOPTS=stackcheck=20percent
You specify stack size in hexadecimal format with the prefix 0x. For example,
XLPGASOPTS=stacksize=0x800kb is equivalent to XLPGASOPTS=stacksize=2mb.
Compiling and running an example program
This section provides a simple UPC program, the commands to compile and execute the
program, and the program output.
In Example 2-8 (hello.upc), each thread prints a message to standard output.
Example 2-8 hello.upc
# include <upc.h>
# include <stdio.h>
int main()
{
printf("Hello world! (THREAD %d of %d THREADS)\n", MYTHREAD, THREADS);
return 0;
}
Use the following command to compile the program in the static environment targeting four
threads:
xlupc -o hello -qupc=threads=4 hello.upc
The compiler compiles the code and generates an executable file, hello. To run the
executable program, you use the following command:
poe ./hello -hostfile hosts -procs 1 -msg_api 'pgas'
In this command, -procs specifies the number of processes to use. The program prints to
standard output a message on each thread, as shown in Example 2-9.
Example 2-9 Output of hello.upc
Hello world! (THREAD 3 of 4 THREADS)
Hello world! (THREAD 1 of 4 THREADS)
Hello world! (THREAD 0 of 4 THREADS)
Hello world! (THREAD 2 of 4 THREADS)
Chapter 2. Application integration
115