1 cfa37a7b 2004-04-10 devnull .TH ARG 3
  2 cfa37a7b 2004-04-10 devnull .SH NAME
  3 cfa37a7b 2004-04-10 devnull ARGBEGIN, ARGEND, ARGC, ARGF, EARGF, arginit, argopt \- process option letters from argv
  4 cfa37a7b 2004-04-10 devnull .SH SYNOPSIS
  5 cfa37a7b 2004-04-10 devnull .B #include <u.h>
  6 cfa37a7b 2004-04-10 devnull .br
  7 cfa37a7b 2004-04-10 devnull .B #include <libc.h>
  8 cfa37a7b 2004-04-10 devnull .PP
  9 cfa37a7b 2004-04-10 devnull .nf
 10 cfa37a7b 2004-04-10 devnull .B ARGBEGIN {
 11 cfa37a7b 2004-04-10 devnull .B char *ARGF();
 12 cfa37a7b 2004-04-10 devnull .B char *EARGF(code);
 13 cfa37a7b 2004-04-10 devnull .B Rune ARGC();
 14 cfa37a7b 2004-04-10 devnull .B } ARGEND
 15 cfa37a7b 2004-04-10 devnull .PP
 16 cfa37a7b 2004-04-10 devnull .B extern char *argv0;
 17 cfa37a7b 2004-04-10 devnull .SH DESCRIPTION
 18 cfa37a7b 2004-04-10 devnull These macros assume the names
 19 cfa37a7b 2004-04-10 devnull .I argc
 20 cfa37a7b 2004-04-10 devnull and
 21 cfa37a7b 2004-04-10 devnull .I argv
 22 cfa37a7b 2004-04-10 devnull are in scope; see
 23 d32deab1 2020-08-16 rsc .MR exec (3) .
 24 cfa37a7b 2004-04-10 devnull .I ARGBEGIN
 25 cfa37a7b 2004-04-10 devnull and
 26 cfa37a7b 2004-04-10 devnull .I ARGEND
 27 cfa37a7b 2004-04-10 devnull surround code for processing program options.
 28 cfa37a7b 2004-04-10 devnull The code
 29 cfa37a7b 2004-04-10 devnull should be the cases of a C switch on
 30 cfa37a7b 2004-04-10 devnull option characters;
 31 cfa37a7b 2004-04-10 devnull it is executed once for each option character.
 32 cfa37a7b 2004-04-10 devnull Options end after an argument 
 33 cfa37a7b 2004-04-10 devnull .BR -- ,
 34 cfa37a7b 2004-04-10 devnull before an argument
 35 cfa37a7b 2004-04-10 devnull .BR - ,
 36 cfa37a7b 2004-04-10 devnull or before an argument that doesn't begin with
 37 cfa37a7b 2004-04-10 devnull .BR - .
 38 cfa37a7b 2004-04-10 devnull .PP
 39 cfa37a7b 2004-04-10 devnull The function macro
 40 cfa37a7b 2004-04-10 devnull .I ARGC
 41 cfa37a7b 2004-04-10 devnull returns the current option character, as an integer.
 42 cfa37a7b 2004-04-10 devnull .PP
 43 cfa37a7b 2004-04-10 devnull The function macro
 44 cfa37a7b 2004-04-10 devnull .I ARGF
 45 cfa37a7b 2004-04-10 devnull returns the current option argument:
 46 cfa37a7b 2004-04-10 devnull a pointer to the rest of the option string if not empty,
 47 cfa37a7b 2004-04-10 devnull or the next argument in
 48 cfa37a7b 2004-04-10 devnull .I argv
 49 cfa37a7b 2004-04-10 devnull if any, or 0.
 50 cfa37a7b 2004-04-10 devnull .I ARGF
 51 cfa37a7b 2004-04-10 devnull must be called just once for each option
 52 cfa37a7b 2004-04-10 devnull that takes an argument.
 53 cfa37a7b 2004-04-10 devnull The macro
 54 cfa37a7b 2004-04-10 devnull .I EARGF
 55 cfa37a7b 2004-04-10 devnull is like
 56 cfa37a7b 2004-04-10 devnull .I ARGF
 57 cfa37a7b 2004-04-10 devnull but instead of returning zero
 58 cfa37a7b 2004-04-10 devnull runs
 59 cfa37a7b 2004-04-10 devnull .I code
 60 cfa37a7b 2004-04-10 devnull and, if that returns, calls
 61 d32deab1 2020-08-16 rsc .MR abort (3) .
 62 cfa37a7b 2004-04-10 devnull A typical value for
 63 cfa37a7b 2004-04-10 devnull .I code
 64 cfa37a7b 2004-04-10 devnull is 
 65 cfa37a7b 2004-04-10 devnull .BR usage() ,
 66 cfa37a7b 2004-04-10 devnull as in
 67 cfa37a7b 2004-04-10 devnull .BR EARGF(usage()) .
 68 cfa37a7b 2004-04-10 devnull .PP
 69 cfa37a7b 2004-04-10 devnull After
 70 cfa37a7b 2004-04-10 devnull .IR ARGBEGIN ,
 71 cfa37a7b 2004-04-10 devnull .I argv0
 72 cfa37a7b 2004-04-10 devnull is a copy of
 73 cfa37a7b 2004-04-10 devnull .BR argv[0]
 74 cfa37a7b 2004-04-10 devnull (conventionally the name of the program).
 75 cfa37a7b 2004-04-10 devnull .PP
 76 cfa37a7b 2004-04-10 devnull After
 77 cfa37a7b 2004-04-10 devnull .IR ARGEND ,
 78 cfa37a7b 2004-04-10 devnull .I argv
 79 cfa37a7b 2004-04-10 devnull points at a zero-terminated list of the remaining
 80 cfa37a7b 2004-04-10 devnull .I argc
 81 cfa37a7b 2004-04-10 devnull arguments.
 82 cfa37a7b 2004-04-10 devnull .SH EXAMPLE
 83 cfa37a7b 2004-04-10 devnull This C program can take option
 84 cfa37a7b 2004-04-10 devnull .B b
 85 cfa37a7b 2004-04-10 devnull and option
 86 cfa37a7b 2004-04-10 devnull .BR f ,
 87 cfa37a7b 2004-04-10 devnull which requires an argument.
 88 cfa37a7b 2004-04-10 devnull .IP
 89 cfa37a7b 2004-04-10 devnull .EX
 90 cfa37a7b 2004-04-10 devnull .ta \w'12345678'u +\w'12345678'u +\w'12345678'u +\w'12345678'u +\w'12345678'u
 91 cfa37a7b 2004-04-10 devnull #include <u.h>
 92 cfa37a7b 2004-04-10 devnull #include <libc.h>
 93 cfa37a7b 2004-04-10 devnull void
 94 cfa37a7b 2004-04-10 devnull main(int argc, char *argv[])
 95 cfa37a7b 2004-04-10 devnull {
 96 cfa37a7b 2004-04-10 devnull 	char *f;
 97 cfa37a7b 2004-04-10 devnull 	print("%s", argv[0]);
 98 cfa37a7b 2004-04-10 devnull 	ARGBEGIN {
 99 cfa37a7b 2004-04-10 devnull 	case 'b':
100 cfa37a7b 2004-04-10 devnull 		print(" -b");
101 cfa37a7b 2004-04-10 devnull 		break;
102 cfa37a7b 2004-04-10 devnull 	case 'f':
103 cfa37a7b 2004-04-10 devnull 		print(" -f(%s)", (f=ARGF())? f: "no arg");
104 cfa37a7b 2004-04-10 devnull 		break;
105 cfa37a7b 2004-04-10 devnull 	default:
106 cfa37a7b 2004-04-10 devnull 		print(" badflag('%c')", ARGC());
107 cfa37a7b 2004-04-10 devnull 	} ARGEND
108 cfa37a7b 2004-04-10 devnull 	print(" %d args:", argc);
109 cfa37a7b 2004-04-10 devnull 	while(*argv)
110 cfa37a7b 2004-04-10 devnull 		print(" '%s'", *argv++);
111 cfa37a7b 2004-04-10 devnull 	print("\en");
112 cfa37a7b 2004-04-10 devnull 	exits(nil);
113 cfa37a7b 2004-04-10 devnull }
114 cfa37a7b 2004-04-10 devnull .EE
115 cfa37a7b 2004-04-10 devnull .PP
116 cfa37a7b 2004-04-10 devnull Here is the output from running the command
117 cfa37a7b 2004-04-10 devnull .B
118 cfa37a7b 2004-04-10 devnull prog -bffile1 -r -f file2 arg1 arg2
119 cfa37a7b 2004-04-10 devnull .IP
120 cfa37a7b 2004-04-10 devnull .B
121 cfa37a7b 2004-04-10 devnull prog -b -f(file1) badflag('r') -f(file2) 2 args: 'arg1' 'arg2'
122 cfa37a7b 2004-04-10 devnull .PP
123 cfa37a7b 2004-04-10 devnull .SH SOURCE
124 c3674de4 2005-01-11 devnull .B \*9/include/libc.h