tusage.c - plan9port - [fork] Plan 9 from user space
  HTML git clone git://src.adamsgaard.dk/plan9port
   DIR Log
   DIR Files
   DIR Refs
   DIR README
   DIR LICENSE
       ---
       tusage.c (1210B)
       ---
            1 #include <u.h>
            2 #include <libc.h>
            3 
            4 void
            5 main(int argc, char **argv)
            6 {
            7         Fmt fmt;
            8         char buf[512];
            9         char *argv0, *args, *flags, *p, *p0;
           10         int single;
           11         Rune r;
           12 
           13         argv0 = getenv("0");
           14         if(argv0 == nil) {
           15                 if(argc > 1)
           16                         argv0 = argv[1];
           17                 else
           18                         argv0 = "unknown-program-name";
           19         }
           20         if((p = strrchr(argv0, '/')) != nil)
           21                 argv0 = p+1;
           22         flags = getenv("flagfmt");
           23         args = getenv("args");
           24 
           25         if(argv0 == nil){
           26                 fprint(2, "aux/usage: $0 not set\n");
           27                 exits("$0");
           28         }
           29         if(flags == nil)
           30                 flags = "";
           31         if(args == nil)
           32                 args = "";
           33 
           34         fmtfdinit(&fmt, 2, buf, sizeof buf);
           35         fmtprint(&fmt, "usage: %s", argv0);
           36         if(flags[0]){
           37                 single = 0;
           38                 for(p=flags; *p; ){
           39                         p += chartorune(&r, p);
           40                         if(*p == ',' || *p == 0){
           41                                 if(!single){
           42                                         fmtprint(&fmt, " [-");
           43                                         single = 1;
           44                                 }
           45                                 fmtprint(&fmt, "%C", r);
           46                                 if(*p == ',')
           47                                         p++;
           48                                 continue;
           49                         }
           50                         while(*p == ' ')
           51                                 p++;
           52                         if(single){
           53                                 fmtprint(&fmt, "]");
           54                                 single = 0;
           55                         }
           56                         p0 = p;
           57                         p = strchr(p0, ',');
           58                         if(p == nil)
           59                                 p = "";
           60                         else
           61                                 *p++ = 0;
           62                         fmtprint(&fmt, " [-%C %s]", r, p0);
           63                 }
           64                 if(single)
           65                         fmtprint(&fmt, "]");
           66         }
           67         if(args)
           68                 fmtprint(&fmt, " %s", args);
           69         fmtprint(&fmt, "\n");
           70         fmtfdflush(&fmt);
           71         exits("usage");
           72 }