什么是通过libcups以编程方式打印双工的正确方法？

Question

这是我目前的方法，不能按预期工作。它只在所有三种情况下打印单面。

#include <cups/cups.h> 

int main(int argc, char *argv[]) 
{ 
cupsSetUser("myuser"); 
cups_dest_t *defaultP = cupsGetDest (NULL, NULL,num_dests,dests); 

int jobid; 
int num_options = 0; 
cups_option_t *options=NULL; 

//SIMPLEX 
num_options = cupsAddOption ("Duplex", "None",num_options,&options); 
jobid = cupsPrintFile(defaultP->name,"/home/myuser/work/TEST.ps","Test Print SIMPLEX", 
         defaultP->num_options,defaultP->options); 
num_options = cupsRemoveOption("Duplex",num_options,&options); 

//DUPLEX Long Edge 
num_options = cupsAddOption ("Duplex", "DuplexNoTumble",num_options,&options); 
jobid = cupsPrintFile(defaultP->name,"/home/myuser/work/TEST.ps","Test Print DUPLEX Long Edge ", 
         defaultP->num_options,defaultP->options); 
num_options = cupsRemoveOption("Duplex",num_options,&options); 

//DUPLEX Short Edge 
num_options = cupsAddOption ("Duplex", "DuplexTumble",num_options,&options); 
jobid = cupsPrintFile(defaultP->name,"/home/myuser/work/TEST.ps","Test Print DUPLEX Short Edge ", 
         defaultP->num_options,defaultP->options); 
num_options = cupsRemoveOption("Duplex",num_options,&options); 
} 

Answer 1

这是正确的方法。每个cupsPrintFile（...）的第二行有错误的参数。应该是num_options, &options而不是defaultP->num_options,defaultP->options。