Packing and Unpacking Data
fmt Printf-like format expression states what to pack. nitem is the total number of items to be packed (not the number of bytes). stride is the stride to be used when packing the items.
Each of the pvm_upk* routines unpacks an array of the specify data type from the active receive buffer. The arguments for each one of the routines are a pointer to the array to be unpacked into, nitem which is the whole number of items to unpack, and stride which is the stride to make use of when unpacking. An exception is pvm_upkstr() which by definition unpacks a NULL terminated character string and therefore does not need nitem or stride arguments.