A print control program for controlling execution of a print job, the print job being shared among printing apparatuses (2, 3), the printing apparatuses (2, 3) comprising a main printing apparatus and one or more sub-printing apparatus(es) and further being connected to a computer through a communication line, the print control program when executed on the computer, causing the computer to function as: a print requesting section for receiving a request to execute a print job in a cooperative manner amongst printing apparatuses; an apparatus information acquiring section for acquiring information relating to printing capabilities of the printing apparatuses as apparatus information, from the main printing apparatus storing the apparatus information; an instruction determining section for determining shares of the print job respectively assigned to the printing apparatuses based upon the acquired apparatus information; and a controlling section for generating control instructions to be transmitted to the printing apparatuses respectively, the control instructions respectively allowing communications between the computer and each of the printing apparatuses, the control instructions being for controlling the execution of the print job; characterized by the print control program further causing the computer to function as an informing section to inform the user of a warning; wherein the main printing apparatus is configured to modifiably store destination(s) of each of the one or more sub-printing apparatus(es), the destination(s) used in the transmission of the control instructions to the respective one or more sub-printing apparatus(es), the apparatus information acquiring section is configured to acquire the apparatus information each time a request is received, the acquired apparatus information further includes the destination(s) of each of the one or more sub-printing apparatus(es), and the informing section is configured to inform, when one of the acquired destination(s) is modified from the destination(s) acquired upon the request for the previous print job, upon the change of destination by displaying the destination(s) acquired for the print job and the destination(s) acquired for the previous print job. a print requesting section for receiving a request to execute a print job in a cooperative manner amongst printing apparatuses; an apparatus information acquiring section for acquiring information relating to printing capabilities of the printing apparatuses as apparatus information, from the main printing apparatus storing the apparatus information; an instruction determining section for determining shares of the print job respectively assigned to the printing apparatuses based upon the acquired apparatus information; and a controlling section for generating control instructions to be transmitted to the printing apparatuses respectively, the control instructions respectively allowing communications between the computer and each of the printing apparatuses, the control instructions being for controlling the execution of the print job; characterized by the print control program further causing the computer to function as an informing section to inform the user of a warning; wherein the main printing apparatus is configured to modifiably store destination(s) of each of the one or more sub-printing apparatus(es), the destination(s) used in the transmission of the control instructions to the respective one or more sub-printing apparatus(es), the apparatus information acquiring section is configured to acquire the apparatus information each time a request is received, the acquired apparatus information further includes the destination(s) of each of the one or more sub-printing apparatus(es), and the informing section is configured to inform, when one of the acquired destination(s) is modified from the destination(s) acquired upon the request for the previous print job, upon the change of destination by displaying the destination(s) acquired for the print job and the destination(s) acquired for the previous print job.