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POPT(3)			   Linux Programmer's Manual		       POPT(3)

NAME
       popt - Parse command line options

SYNOPSIS
       #include <popt.h>

       poptContext poptGetContext(const char * name, int argc,
				  const char ** argv,
				  const struct poptOption * options,
				  int flags);

       void poptFreeContext(poptContext con);

       void poptResetContext(poptContext con);

       int poptGetNextOpt(poptContext con);

       const char * poptGetOptArg(poptContext con);

       const char * poptGetArg(poptContext con);

       const char * poptPeekArg(poptContext con);

       const char ** poptGetArgs(poptContext con);

       const char *const poptStrerror(const int error);

       const char * poptBadOption(poptContext con, int flags);

       int poptReadDefaultConfig(poptContext con, int flags);

       int poptReadConfigFile(poptContext con, char * fn);

       int poptAddAlias(poptContext con, struct poptAlias alias,
			int flags);

       int poptParseArgvString(char * s, int *	argcPtr,
			       const char *** argvPtr);

       int poptDupArgv(int argc, const char ** argv, int * argcPtr,
			       const char *** argvPtr);

       int poptStuffArgs(poptContext con, const char ** argv);

DESCRIPTION
       The  popt  library exists essentially for parsing command-line options.
       It is found superior in many ways when compared	to  parsing  the  argv
       array  by hand or using the getopt functions getopt() and getopt_long()
       [see getopt(3)].	 Some specific advantages of popt  are:	 it  does  not
       utilize global variables, thus enabling multiple passes in parsing argv
       ; it can parse an arbitrary  array  of  argv-style  elements,  allowing
       parsing of command-line-strings from any source; it provides a standard
       method of option aliasing (to be discussed at length  below.);  it  can
       exec external option filters; and, finally, it can automatically gener‐
       ate help and usage messages for the application.

       Like getopt_long(), the popt library  supports  short  and  long	 style
       options.	 Recall that a short option consists of a - character followed
       by a single alphanumeric character.  A long option, common in GNU util‐
       ities,  consists	 of  two  - characters followed by a string made up of
       letters, numbers and hyphens.  Long options are optionally  allowed  to
       begin  with  a  single -, primarily to allow command-line compatibility
       between popt applications and X toolkit applications.  Either  type  of
       option  may  be	followed  by  an  argument.  A space separates a short
       option from its arguments; either a space or  an	 =  separates  a  long
       option from an argument.

       The  popt library is highly portable and should work on any POSIX plat‐
       form.  The latest version is distributed with rpm and is always	avail‐
       able from: ftp://ftp.rpm.org/pub/rpm/dist.

       It  may	be  redistributed under the X consortium license, see the file
       COPYING in the popt source distribution for details.

BASIC POPT USAGE
   1. THE OPTION TABLE
       Applications  provide  popt  with  information  on  their  command-line
       options by means of an "option table," i.e., an array of struct poptOp‐
       tion structures:

       #include <popt.h>

       struct poptOption {
	   const char * longName; /* may be NULL */
	   char shortName;	  /* may be '\0' */
	   int argInfo;
	   void * arg;		  /* depends on argInfo */
	   int val;		  /* 0 means don't return, just update flag */
	   char * descrip;	  /* description for autohelp -- may be NULL */
	   char * argDescrip;	  /* argument description for autohelp */
       };

       Each member of the table defines a single option that may be passed  to
       the  program.   Long  and  short options are considered a single option
       that may occur in two different forms.  The first two members, longName
       and  shortName,	define	the  names  of the option; the first is a long
       name, while the latter is a single character.

       The argInfo member tells popt what type of argument is  expected	 after
       the  argument.  If no option is expected, POPT_ARG_NONE should be used.
       The rest of the valid values are shown in the following table:

       Value		 Description			    arg Type
       POPT_ARG_NONE	 No argument expected		    int
       POPT_ARG_STRING	 No type checking to be performed   char *
       POPT_ARG_INT	 An integer argument is expected    int
       POPT_ARG_LONG	 A long integer is expected	    long
       POPT_ARG_VAL	 Integer value taken from val	    int
       POPT_ARG_FLOAT	 An float argument is expected	    float
       POPT_ARG_DOUBLE	 A double argument is expected	    double

       For numeric values, if the argInfo value is bitwise or'd	 with  one  of
       POPT_ARGFLAG_OR,	 POPT_ARGFLAG_AND,  or	POPT_ARGFLAG_XOR, the value is
       saved by performing an OR, AND, or XOR.	If the argInfo value  is  bit‐
       wise  or'd with POPT_ARGFLAG_NOT, the value will be negated before sav‐
       ing. For	 the  common  operations  of  setting  and/or  clearing	 bits,
       POPT_BIT_SET and POPT_BIT_CLR have the appropriate flags set to perform
       bit operations.

       If the argInfo value is bitwise	or'd  with  POPT_ARGFLAG_ONEDASH,  the
       long argument may be given with a single - instead of two. For example,
       if --longopt is an  option  with	 POPT_ARGFLAG_ONEDASH,	is  specified,
       -longopt is accepted as well.

       The  next  element,  arg,  allows  popt to automatically update program
       variables when the option is used. If arg is NULL, it  is  ignored  and
       popt  takes no special action.  Otherwise it should point to a variable
       of the type indicated in the right-most column of the table above.

       If the option takes no argument (argInfo is POPT_ARG_NONE),  the	 vari‐
       able  pointed to by arg is set to 1 when the option is used.  (Inciden‐
       tally, it will perhaps not escape the attention of  hunt-and-peck  typ‐
       ists that the value of POPT_ARG_NONE is 0.)  If the option does take an
       argument, the variable that arg points to is  updated  to  reflect  the
       value  of  the  argument.  Any string is acceptable for POPT_ARG_STRING
       arguments,  but	POPT_ARG_INT,	POPT_ARG_LONG,	 POPT_ARG_FLOAT,   and
       POPT_ARG_DOUBLE	are  converted	to  the appropriate type, and an error
       returned if the conversion fails.

       POPT_ARG_VAL causes arg to be set to the (integer) value	 of  val  when
       the  argument  is found.	 This is most often useful for mutually-exclu‐
       sive arguments in cases where it is not an error for multiple arguments
       to  occur  and  where  you want the last argument specified to win; for
       example, "rm -i -f".  POPT_ARG_VAL causes the parsing function  not  to
       return a value, since the value of val has already been used.

       If  the	argInfo	 value is bitwise or'd with POPT_ARGFLAG_OPTIONAL, the
       argument to the long option may be omitted. If the long option is  used
       without	an argument, a default value of zero or NULL will be saved (if
       the arg pointer is present), otherwise behavior will be identical to  a
       long option with argument.

       The  next  option,  val,	 is  the  value popt's parsing function should
       return when the option is encountered.  If it is 0, the	parsing	 func‐
       tion  does  not	return	a value, instead parsing the next command-line
       argument.

       The last two options, descrip and argDescrip are only required if auto‐
       matic help messages are desired (automatic usage messages can be gener‐
       ated without them). descrip is a text description of the	 argument  and
       argdescrip  is  a  short	 summary  of  the type of arguments the option
       expects, or NULL if the option doesn't require any arguments.

       If popt should automatically provide --usage and --help (-?)   options,
       one  line  in  the table should be the macro POPT_AUTOHELP.  This macro
       includes another option table (via POPT_ARG_INCLUDE_TABLE;  see	below)
       in  the	main one which provides the table entries for these arguments.
       When --usage or --help are passed to programs which use popt's automat‐
       ical  help,  popt displays the appropriate message on stderr as soon as
       it finds the option, and exits the program with a return code of 0.  If
       you  want  to  use popt's automatic help generation in a different way,
       you need to explicitly add the option entries to your  programs	option
       table instead of using POPT_AUTOHELP.

       If  the argInfo value is bitwise or'd with POPT_ARGFLAG_DOC_HIDDEN, the
       argument will not be shown in help output.

       If the argInfo value is bitwise	or'd  with  POPT_ARGFLAG_SHOW_DEFAULT,
       the inital value of the arg will be shown in help output.

       The final structure in the table should have all the pointer values set
       to NULL and all the arithmetic values set to 0, marking the end of  the
       table. The macro POPT_TABLEEND is provided to do that.

       There  are  two types of option table entries which do not specify com‐
       mand line options. When either of these types of entries are used,  the
       longName element must be NULL and the shortName element must be '\0'.

       The  first  of these special entry types allows the application to nest
       another option table in the current one; such nesting may extend	 quite
       deeply  (the actual depth is limited by the program's stack). Including
       other option tables allows a library to provide a standard set of  com‐
       mand-line options to every program which uses it (this is often done in
       graphical programming toolkits, for  example).  To  do  this,  set  the
       argInfo	field  to POPT_ARG_INCLUDE_TABLE and the arg field to point to
       the table which is being included.  If  automatic  help	generation  is
       being  used,  the descrip field should contain a overall description of
       the option table being included.

       The other special option table entry type tells popt to call a function
       (a callback) when any option in that table is found. This is especially
       usefull when included option tables are	being  used,  as  the  program
       which  provides	the top-level option table doesn't need to be aware of
       the other options which are provided by	the  included  table.  When  a
       callback	 is set for a table, the parsing function never returns infor‐
       mation on an option in the table. Instead, options information must  be
       retained	 via the callback or by having popt set a variable through the
       option's arg field.  Option callbacks should match the following proto‐
       type:

       void poptCallbackType(poptContext con,
			     const struct poptOption * opt,
			     const char * arg, void * data);

       The  first parameter is the context which is being parsed (see the next
       section for information on contexts), opt points to  the	 option	 which
       triggered  this	callback,  and	arg  is the option's argument.	If the
       option does not take an argument, arg is NULL.	The  final  parameter,
       data  is	 taken	from the descrip field of the option table entry which
       defined the callback. As descrip is a  pointer,	this  allows  callback
       functions to be passed an arbitrary set of data (though a typecast will
       have to be used).

       The option table entry which defines  a	callback  has  an  argInfo  of
       POPT_ARG_CALLBACK,  an arg which points to the callback function, and a
       descrip field which specifies an arbitrary pointer to be passed to  the
       callback.

   2. CREATING A CONTEXT
       popt  can  interleave  the  parsing  of	multiple command-line sets. It
       allows this by keeping all the state information for a  particular  set
       of  command-line	 arguments  in a poptContext data structure, an opaque
       type that should not be modified outside the popt library.

       New popt contexts are created by poptGetContext():

       poptContext poptGetContext(const char * name, int argc,
				  const char ** argv,
				  const struct poptOption * options,
				  int flags);

       The first parameter, name, is used only for alias  handling  (discussed
       later).	It  should  be	the  name of the application whose options are
       being parsed, or should be NULL if no option aliasing is	 desired.  The
       next  two  arguments specify the command-line arguments to parse. These
       are generally passed to poptGetContext() exactly as they were passed to
       the  program's main() function. The options parameter points to the ta‐
       ble of command-line options, which was described in the	previous  sec‐
       tion. The final parameter, flags, can take one of three values:

       Value			    Description
       POPT_CONTEXT_NO_EXEC	    Ignore exec expansions
       POPT_CONTEXT_KEEP_FIRST	    Do not ignore argv[0]
       POPT_CONTEXT_POSIXMEHARDER   Options cannot follow arguments

       A poptContext keeps track of which options have already been parsed and
       which remain, among other things. If a program wishes to restart option
       processing of a set of arguments, it can reset the poptContext by pass‐
       ing the context as the sole argument to poptResetContext().

       When argument processing is complete, the process should free the popt‐
       Context	as  it	contains  dynamically  allocated components. The popt‐
       FreeContext() function takes a poptContext as  its  sole	 argument  and
       frees the resources the context is using.

       Here  are  the  prototypes  of both poptResetContext() and poptFreeCon‐
       text():

       #include <popt.h>
       void poptFreeContext(poptContext con);
       void poptResetContext(poptContext con);

   3. PARSING THE COMMAND LINE
       After an application has created a poptContext, it  may	begin  parsing
       arguments. poptGetNextOpt() performs the actual argument parsing.

       #include <popt.h>
       int poptGetNextOpt(poptContext con);

       Taking  the context as its sole argument, this function parses the next
       command-line argument found. After finding the  next  argument  in  the
       option table, the function fills in the object pointed to by the option
       table entry's arg pointer if it is not NULL. If the val entry  for  the
       option is non-0, the function then returns that value. Otherwise, popt‐
       GetNextOpt() continues on to the next argument.

       poptGetNextOpt() returns -1 when the final argument  has	 been  parsed,
       and  other negative values when errors occur. This makes it a good idea
       to keep the val elements in the options table greater than 0.

       If all of the command-line options are handled  through	arg  pointers,
       command-line parsing is reduced to the following line of code:

       rc = poptGetNextOpt(poptcon);

       Many  applications require more complex command-line parsing than this,
       however, and use the following structure:

       while ((rc = poptGetNextOpt(poptcon)) > 0) {
	    switch (rc) {
		 /* specific arguments are handled here */
	    }
       }

       When returned options are handled, the application needs	 to  know  the
       value  of any arguments that were specified after the option. There are
       two ways to discover them. One is to ask popt to	 fill  in  a  variable
       with  the  value of the option through the option table's arg elements.
       The other is to use poptGetOptArg():

       #include <popt.h>
       const char * poptGetOptArg(poptContext con);

       This function returns the argument given for the final option  returned
       by poptGetNextOpt(), or it returns NULL if no argument was specified.

   4. LEFTOVER ARGUMENTS
       Many  applications  take an arbitrary number of command-line arguments,
       such as a list of file names. When popt	encounters  an	argument  that
       does  not begin with a -, it assumes it is such an argument and adds it
       to a list of leftover arguments. Three functions allow applications  to
       access such arguments:

       const char * poptGetArg(poptContext con);
	      This function returns the next leftover argument and marks it as
	      processed.

       const char * poptPeekArg(poptContext con);
	      The next leftover argument is returned but not  marked  as  pro‐
	      cessed.  This allows an application to look ahead into the argu‐
	      ment list, without modifying the list.

       const char ** poptGetArgs(poptContext con);
	      All the leftover arguments are returned in a manner identical to
	      argv.   The  final element in the returned array points to NULL,
	      indicating the end of the arguments.

   5. AUTOMATIC HELP MESSAGES
       The  popt  library  can	automatically  generate	 help  messages	 which
       describe	 the  options  a  program accepts. There are two types of help
       messages which can be generated. Usage messages are  a  short  messages
       which  lists  valid  options, but does not describe them. Help messages
       describe each option on one (or more) lines, resulting in a longer, but
       more  useful,  message.	Whenever automatic help messages are used, the
       descrip and argDescrip  fields  struct  poptOption  members  should  be
       filled in for each option.

       The  POPT_AUTOHELP  macro  makes it easy to add --usage and --help mes‐
       sages to your program, and is described in part 1 of this man page.  If
       more control is needed over your help messages, the following two func‐
       tions are available:

       #include <popt.h>
       void poptPrintHelp(poptContext con, FILE * f, int flags);
       void poptPrintUsage(poptContext con, FILE * f, int flags);

       poptPrintHelp() displays the standard help message to  the  stdio  file
       descriptor  f,  while  poptPrintUsage() displays the shorter usage mes‐
       sage. Both functions currently ignore the flags argument; it  is	 there
       to allow future changes.

ERROR HANDLING
       All of the popt functions that can return errors return integers.  When
       an error occurs, a negative error code is returned. The following table
       summarizes the error codes that occur:

	    Error		       Description
       POPT_ERROR_NOARG	      Argument missing for an option.
       POPT_ERROR_BADOPT      Option's argument couldn't be parsed.
       POPT_ERROR_OPTSTOODEEP Option aliasing nested too deeply.
       POPT_ERROR_BADQUOTE    Quotations do not match.
       POPT_ERROR_BADNUMBER   Option couldn't be converted to number.
       POPT_ERROR_OVERFLOW    A given number was too big or small.

       Here is a more detailed discussion of each error:

       POPT_ERROR_NOARG
	      An option that requires an argument was specified on the command
	      line, but no argument was given. This can be  returned  only  by
	      poptGetNextOpt().

       POPT_ERROR_BADOPT
	      An  option was specified in argv but is not in the option table.
	      This error can be returned only from poptGetNextOpt().

       POPT_ERROR_OPTSTOODEEP
	      A set of option aliases is nested too  deeply.  Currently,  popt
	      follows  options	only  10 levels to prevent infinite recursion.
	      Only poptGetNextOpt() can return this error.

       POPT_ERROR_BADQUOTE
	      A parsed string has a quotation mismatch (such as a single  quo‐
	      tation  mark).  poptParseArgvString(),  poptReadConfigFile(), or
	      poptReadDefaultConfig() can return this error.

       POPT_ERROR_BADNUMBER
	      A conversion from a string to a number (int or long) failed  due
	      to the string containing nonnumeric characters. This occurs when
	      poptGetNextOpt() is processing an argument of type POPT_ARG_INT,
	      POPT_ARG_LONG, POPT_ARG_FLOAT, or POPT_ARG_DOUBLE.

       POPT_ERROR_OVERFLOW
	      A	 string-to-number conversion failed because the number was too
	      large or too small. Like POPT_ERROR_BADNUMBER,  this  error  can
	      occur  only  when	 poptGetNextOpt() is processing an argument of
	      type    POPT_ARG_INT,    POPT_ARG_LONG,	 POPT_ARG_FLOAT,    or
	      POPT_ARG_DOUBLE.

       POPT_ERROR_ERRNO
	      A	 system	 call returned with an error, and errno still contains
	      the error from the system call.  Both  poptReadConfigFile()  and
	      poptReadDefaultConfig() can return this error.

       Two functions are available to make it easy for applications to provide
       good error messages.

	      const char *const poptStrerror(const int error);
	      This function takes a popt  error	 code  and  returns  a	string
	      describing the error, just as with the standard strerror() func‐
	      tion.

	      const char * poptBadOption(poptContext con, int flags);
	      If an error  occurred  during  poptGetNextOpt(),	this  function
	      returns  the option that caused the error. If the flags argument
	      is  set  to  POPT_BADOPTION_NOALIAS,  the	 outermost  option  is
	      returned.	 Otherwise,  flags should be 0, and the option that is
	      returned may have been specified through an alias.

       These two functions make popt error handling trivial for most  applica‐
       tions.  When  an error is detected from most of the functions, an error
       message is printed along with the  error	 string	 from  poptStrerror().
       When an error occurs during argument parsing, code similiar to the fol‐
       lowing displays a useful error message:

       fprintf(stderr, "%s: %s\n",
	       poptBadOption(optCon, POPT_BADOPTION_NOALIAS),
	       poptStrerror(rc));

OPTION ALIASING
       One of the primary benefits of using popt over getopt() is the  ability
       to  use	option	aliasing. This lets the user specify options that popt
       expands into other options when they are	 specified.  If	 the  standard
       grep  program  made  use	 of popt, users could add a --text option that
       expanded to -i -n -E -2 to let them more	 easily	 find  information  in
       text files.

   1. SPECIFYING ALIASES
       Aliases	are  normally specified in two places: /etc/popt and the .popt
       file in the user's home directory (found through the  HOME  environment
       variable).  Both	 files	have  the  same format, an arbitrary number of
       lines formatted like this:

       appname alias newoption expansion

       The appname is the name of the application, which must be the  same  as
       the name parameter passed to poptGetContext(). This allows each file to
       specify aliases for multiple programs. The alias keyword specifies that
       an  alias  is being defined; currently popt configuration files support
       only aliases, but other abilities may be added in the future. The  next
       option  is  the	option	that should be aliased, and it may be either a
       short or a long option. The rest of the line  specifies	the  expansion
       for  the alias. It is parsed similarly to a shell command, which allows
       \, ", and ' to be used for quoting. If a backslash is the final charac‐
       ter  on	a  line,  the next line in the file is assumed to be a logical
       continuation of the line containing the backslash, just as in shell.

       The following entry would add a --text option to the grep  command,  as
       suggested at the beginning of this section.

       grep alias --text -i -n -E -2

   2. ENABLING ALIASES
       An  application	must  enable  alias expansion for a poptContext before
       calling poptGetNextArg() for the first time. There are three  functions
       that define aliases for a context:

	      int poptReadDefaultConfig(poptContext con, int flags);
	      This function reads aliases from /etc/popt and the .popt file in
	      the user's home directory. Currently, flags should be  NULL,  as
	      it is provided only for future expansion.

	      int poptReadConfigFile(poptContext con, char * fn);
	      The file specified by fn is opened and parsed as a popt configu‐
	      ration file. This allows programs to use	program-specific  con‐
	      figuration files.

	      int poptAddAlias(poptContext con, struct poptAlias alias,
			       int flags);
	      Occasionally,  processes	want to specify aliases without having
	      to read them from a configuration file. This function adds a new
	      alias  to	 a  context.  The flags argument should be 0, as it is
	      currently reserved for future expansion. The new alias is speci‐
	      fied as a struct poptAlias, which is defined as:

	      struct poptAlias {
		   const char * longName; /* may be NULL */
		   char shortName; /* may be '\0' */
		   int argc;
		   const char ** argv; /* must be free()able */
	      };

	      The  first  two  elements,  longName  and shortName, specify the
	      option that is aliased. The final two, argc and argv, define the
	      expansion to use when the aliases option is encountered.

PARSING ARGUMENT STRINGS
       Although	 popt  is  usually  used for parsing arguments already divided
       into an argv-style array, some programs need to parse strings that  are
       formatted  identically  to command lines. To facilitate this, popt pro‐
       vides a function that parses a string into an array of  strings,	 using
       rules similiar to normal shell parsing.

       #include <popt.h>
       int poptParseArgvString(char * s, int * argcPtr,
			       char *** argvPtr);
       int poptDupArgv(int argc, const char ** argv, int * argcPtr,
			       const char *** argvPtr);

       The string s is parsed into an argv-style array. The integer pointed to
       by the argcPtr parameter contains the number of	elements  parsed,  and
       the  final  argvPtr parameter contains the address of the newly created
       array.  The routine poptDupArgv() can be used to	 make  a  copy	of  an
       existing argument array.

       The  argvPtr created by poptParseArgvString() or poptDupArgv() is suit‐
       able to pass directly to poptGetContext().  Both routines return a sin‐
       gle  dynamically	 allocated  contiguous	block of storage and should be
       free()ed when the application is finished with the storage.

HANDLING EXTRA ARGUMENTS
       Some applications implement the equivalent of option aliasing but  need
       to  do so through special logic. The poptStuffArgs() function allows an
       application to insert new arguments into the current poptContext.

       #include <popt.h>
       int poptStuffArgs(poptContext con, const char ** argv);

       The passed argv must have a NULL pointer as  its	 final	element.  When
       poptGetNextOpt()	 is next called, the "stuffed" arguments are the first
       to be parsed. popt returns to the normal arguments once all the stuffed
       arguments have been exhausted.

EXAMPLE
       The  following  example	is a simplified version of the program "robin"
       which appears in Chapter 15 of the text cited below.   Robin  has  been
       stripped	  of  everything  but  its  argument-parsing  logic,  slightly
       reworked, and renamed "parse." It may prove useful in  illustrating  at
       least some of the features of the extremely rich popt library.

       #include <popt.h>
       #include <stdio.h>

       void usage(poptContext optCon, int exitcode, char *error, char *addl) {
	   poptPrintUsage(optCon, stderr, 0);
	   if (error) fprintf(stderr, "%s: %s0, error, addl);
	   exit(exitcode);
       }

       int main(int argc, char *argv[]) {
	  char	  c;		/* used for argument parsing */
	  int	  i = 0;	/* used for tracking options */
	  char	  *portname;
	  int	  speed = 0;	/* used in argument parsing to set speed */
	  int	  raw = 0;	/* raw mode? */
	  int	  j;
	  char	  buf[BUFSIZ+1];
	  poptContext optCon;	/* context for parsing command-line options */

	  struct poptOption optionsTable[] = {
				     { "bps", 'b', POPT_ARG_INT, &speed, 0,
								   "signaling rate in bits-per-second", "BPS" },
				     { "crnl", 'c', 0, 0, 'c',
								   "expand cr characters to cr/lf sequences" },
				     { "hwflow", 'h', 0, 0, 'h',
								   "use hardware (RTS/CTS) flow control" },
				     { "noflow", 'n', 0, 0, 'n',
								   "use no flow control" },
				     { "raw", 'r', 0, &raw, 0,
								   "don't perform any character conversions" },
				     { "swflow", 's', 0, 0, 's',
								   "use software (XON/XOF) flow control" } ,
				     POPT_AUTOHELP
				     { NULL, 0, 0, NULL, 0 }
	  };

	  optCon = poptGetContext(NULL, argc, argv, optionsTable, 0);
	  poptSetOtherOptionHelp(optCon, "[OPTIONS]* <port>");

	  if (argc < 2) {
				 poptPrintUsage(optCon, stderr, 0);
				 exit(1);
	  }

	  /* Now do options processing, get portname */
	  while ((c = poptGetNextOpt(optCon)) >= 0) {
	     switch (c) {
		case 'c':
		   buf[i++] = 'c';
		   break;
		case 'h':
		   buf[i++] = 'h';
		   break;
		case 's':
		   buf[i++] = 's';
		   break;
		case 'n':
		   buf[i++] = 'n';
		   break;
	     }
	  }
	  portname = poptGetArg(optCon);
	  if((portname == NULL) || !(poptPeekArg(optCon) == NULL))
	     usage(optCon, 1, "Specify a single port", ".e.g., /dev/cua0");

	  if (c < -1) {
	     /* an error occurred during option processing */
	     fprintf(stderr, "%s: %s\n",
		     poptBadOption(optCon, POPT_BADOPTION_NOALIAS),
		     poptStrerror(c));
	     return 1;
	  }

	  /* Print out options, portname chosen */
	  printf("Options  chosen: ");
	  for(j = 0; j < i ; j++)
	     printf("-%c ", buf[j]);
	  if(raw) printf("-r ");
	  if(speed) printf("-b %d ", speed);
	  printf("\nPortname chosen: %s\n", portname);

	  poptFreeContext(optCon);
	  exit(0);
       }

       RPM,  a	popular	 Linux	package management program, makes heavy use of
       popt's features. Many of its  command-line  arguments  are  implemented
       through	popt  aliases,	which makes RPM an excellent example of how to
       take advantage of the popt library. For more information	 on  RPM,  see
       http://www.rpm.org.  The	 popt  source  code distribution includes test
       program(s) which use all of the features of the popt libraries in vari‐
       ous ways. If a feature isn't working for you, the popt test code is the
       first place to look.

BUGS
       None presently known.

AUTHOR
       Erik W. Troan <ewt@redhat.com>

       This man page is derived in part from Linux Application Development  by
       Michael	K.  Johnson  and  Erik W. Troan, Copyright (c) 1998 by Addison
       Wesley Longman, Inc., and included in the popt documentation  with  the
       permission of the Publisher and the appreciation of the Authors.

       Thanks to Robert Lynch for his extensive work on this man page.

SEE ALSO
       getopt(3)

       Linux  Application Development, by Michael K. Johnson and Erik W. Troan
       (Addison-Wesley, 1998; ISBN 0-201-30821-5), Chapter 24.

       popt.ps is a Postscript version of the above cited book chapter. It can
       be   found   in	 the   source	archive	  for	popt   available   at:
       ftp://ftp.rpm.org/pub/rpm.

				 June 30, 1998			       POPT(3)
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