Name
       mkconfig_c - mkconfig C language units

Description
       The C language units create an include file for use by C programs.

C Language Units
       c-main
	      The c-main unit creates an include file for C programs.  The hdr
	      and sys directives should be listed first in the	mkconfig  con‐
	      figuration file so that the headers are available for use in the
	      other tests.

	      standard
		     The standard checks are: the headers  stdio.h,  stdlib.h,
		     sys/types.h and sys/param.h, the keywords void and const,
		     the void * type as a parameter,  and  C  function	proto‐
		     types.

		     Output:
		     #define _hdr_stdio 1
		     #define _hdr_stdlib 1
		     #define _sys_types 1
		     #define _sys_param 1
		     #define _key_void 1
		     #define _key_const 1
		     #define _param_void_star 1
		     #define _proto_stdc 1

	      args [noconst] name-of-function
		     Checks  the  number  of arguments, the types of the argu‐
		     ments and the return type for a function.	 If  'noconst'
		     is  specified,  any  data	type is returned.  Outputs the
		     following check variables: _args_function, _c_arg_N_func‐
		     tion, and _c_type_function.  _args_function indicates the
		     number  of  arguments.  _c_arg_N_function	indicates  the
		     argument	data  type.   _c_type_function	indicates  the
		     return type of the function.   The  'awk'	program  is  a
		     requirement for this directive.

		     e.g.
		     args noconst setmntent
		     Output:
		     #define _c_arg_1_setmntent char *
		     #define _c_arg_2_setmntent char *
		     #define _c_type_setmntent FILE *
		     #define _args_setmntent 2

	      hdr name-of-header [required-headers]
		     Check  for a header.  The standard include path as set in
		     CFLAGS is used.  If required-headers is specified,  those
		     headers  are  included  in  the  compilation  test before
		     attempting the compilation test.

		     e.g.
		     hdr getopt
		     hdr storage/volumes.h gui/window.h
		     Output:
		     #define _hdr_getopt 1
		     #define _hdr_storage_volumes 0

	      sys name-of-sys-header [required-headers]
		     Like hdr, but looks in the sys/ directory.

		     e.g.
		     sys types.h
		     Output:
		     #define _sys_types 1

	      class class [libs, ...]
		     Check to see if class class exists.  If the optional libs
		     are  specified,  the  test  will  try  first  without the
		     libraries, then with the first set  of  libraries	speci‐
		     fied,  then  the  next set, etc.  Sets of libraries to be
		     tested are separated by commas.

		     e.g.
		     class os::Volumes
		     Output:
		     #define _class_os__Volumes 0

		     Execute mkc.sh -reqlib after creating the output file  to
		     output the libraries required for linking.  See the usage
		     for mkc.sh -reqlib in the lib check below.

	      const constant-name [required-headers]
		     Check to see that a constant exists.  If required-headers
		     is  specified, those headers are included in the compila‐
		     tion test before attempting the compilation test.

		     e.g.
		     const O_NOCTTY
		     Output:
		     #define _const_O_NOCTTY 1

	      dcl {int|ptr} variable-name
		     Check to see if variable-name is  declared.   If  int  is
		     specified,  the  variable	is  a numeric type.  If ptr is
		     specified, the variable is a pointer type.

		     e.g.
		     dcl int errno
		     dcl ptr optarg
		     Output:
		     #define _dcl_errno 1
		     #define _dcl_optarg 1

	      define definition-name
		     Check to see if definition-name is defined.

		     e.g.
		     define MCTL_QUERY
		     Output:
		     #define _define_MCTL_QUERY 0

	      key keyword
		     Check to see if a C-language keyword is reserved.

		     e.g.
		     key volatile
		     Output:
		     #define _key_volatile 1

	      lib function [libs, ...]
		     Check to see if the library function function exists.  If
		     the  optional libs are specified, the test will try first
		     without  the  libraries,  then  with  the	first  set  of
		     libraries	specified  linked  in, then the next set, etc.
		     Sets of libraries to be tested are separated  by  commas.
		     If  link  libraries are specified, any value in the cache
		     is ignored, and the function is retested.

		     e.g.
		     lib gettext -lintl, -lintl -liconv
		     [Will first test gettext, then gettext -lintl,
		      then gettext -lintl -liconv]
		     Output:
		     #define _lib_gettext 1

		     Execute mkc.sh -reqlib after creating the output file  to
		     output the libraries required for linking.

		     mkc.sh -reqlib creates the list of libraries required for
		     linking based on the output file.	This allows  the  user
		     to   modify  the  output  file  and  only	the  necessary
		     libraries will be linked in.

		     mkc.sh -reqlib is executed with a command	line  argument
		     of the output file name created by mkconfig.sh.  The out‐
		     put library file defaults to 'mkconfig.reqlibs', but  may
		     be changed with the -o command line option.

		     The  string  '_dollar_', if included in the library func‐
		     tion name will be replaced with the '$' symbol.

	      member struct struct-name member

	      member union union-name member

	      member typedef-name member
		     Check to see if member is a member of struct  struct-name
		     or typedef-name.

		     e.g.
		     member struct statfs f_bsize
		     Output:
		     #define _mem_struct_statfs_f_bsize 1

	      memberxdr struct-name member
		     Define  the appropriate xdr function for struct-name.mem‐
		     ber.  The 'awk' program is a requirement for this	direc‐
		     tive.

		     e.g.
		     memberxdr getquota_args gqa_uid
		     Output:
		     #define xdr_gqa_uid xdr_int
		     #define _memberxdr_getquota_args_gqa_uid 1

	      npt function [library-requirement]
		     Check  to	see  if  if function needs to have a prototype
		     declared.	The  optional  library-requirement  should  be
		     written as: _lib_.  If library-requirement does
		     not exist, _npt_ will be set to	false  in  the
		     output file.

		     e.g.
		     npt getopt
		     npt statfs _lib_statfs
		     Output:
		     #define _npt_getopt 0
		     #define _npt_statfs 0

	      siz type-name
		     Check the size of type-name.

		     e.g.
		     siz long long
		     Output:
		     #define _siz_long_long 8

	      typ type-name
		     Check  to	see if a type-name exists.  type-name may be a
		     type or a structure.

		     e.g.
		     typ size_t
		     typ struct dqblk
		     Output:
		     #define _typ_size_t 1
		     #define _typ_struct_dqblk 1

       c-include-conflict

	      include_conflict  
		     Check to see if there is a compile conflict when  includ‐
		     ing two headers.  If there is a conflict, the check vari‐
		     able is set to 0.

		     e.g.
		     include_conflict time.h sys/time.h
		     Output:
		     #define _inc_conflict__hdr_time__sys_time 1

See Also
       iffe(1) autoconf(1) dist(7) mkconfig(7) mkconfig_env(7) mkconfig_d(7)

Bugs
       Send bug reports to: brad.lanam.di_at_gmail.com

Website
       http://www.gentoo.com/di/mkconfig.html

Author
       This program is Copyright 2011 by Brad Lanam, Walnut Creek CA

       Brad Lanam, Walnut Creek, CA (brad.lanam.di_at_gmail.com)