popt man page on Gentoo

Man page or keyword search:  
man Server   6889 pages
apropos Keyword Search (all sections)
Output format
Gentoo logo
[printable version]

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  option.  If no argument 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_ARGV	   No type checking to be performed   char **
       POPT_ARG_SHORT	   An short argument is expected      short
       POPT_ARG_INT	   An integer argument is expected    int
       POPT_ARG_LONG	   A long integer is expected	      long
       POPT_ARG_LONGLONG   A long long integer is expected    long 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.  A
       POPT_ARG_ARGV  arg  will (re-)allocate an array of char * string point‐
       ers, append the string argument, and add a NULL sentinel at the end  of
       the array as needed.  The target char ** address of a POPT_ARG_ARGV arg
       should be initialized to NULL.

       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
       and  POPT_ARG_ARGV   arguments,	 but   POPT_ARG_INT,   POPT_ARG_SHORT,
       POPT_ARG_LONG,  POPT_ARG_LONGLONG,  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>
       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.
       The calling function is responsible for deallocating this string.

   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_SHORT,	      POPT_ARG_LONG,	    POPT_ARG_LONGLONG,
	      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_SHORT, POPT_ARG_LONG, POPT_ARG_LONG‐
	      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", NULL },
	     { "hwflow", 'h', 0, 0, 'h',
				 "use hardware (RTS/CTS) flow control", NULL },
	     { "noflow", 'n', 0, 0, 'n',
				 "use no flow control", NULL },
	     { "raw", 'r', 0, &raw, 0,
				 "don't perform any character conversions", NULL },
	     { "swflow", 's', 0, 0, 's',
				 "use software (XON/XOF) flow control", NULL } ,
	     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)
[top]

List of man pages available for Gentoo

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net