autoconf.info: Autoheader Macros

Go backward to autoheader Invocation
Go up to Configuration Headers
Go to the top op autoconf

Autoheader Macros

`autoheader' scans `configure.ac' and figures out which C preprocessor
symbols it might define.  It knows how to generate templates for
symbols defined by `AC_CHECK_HEADERS', `AC_CHECK_FUNCS' etc., but if
you `AC_DEFINE' any additional symbol, you must define a template for
it.  If there are missing templates, `autoheader' fails with an error
message.
   The simplest way to create a template for a SYMBOL is to supply the
DESCRIPTION argument to an `AC_DEFINE(SYMBOL)'; see *Note Defining
Symbols::.  You may also use one of the following macros.
 - Macro: AH_VERBATIM (KEY, TEMPLATE)
     Tell `autoheader' to include the TEMPLATE as-is in the header
     template file.  This TEMPLATE is associated with the KEY, which is
     used to sort all the different templates and guarantee their
     uniqueness.  It should be a symbol that can be `AC_DEFINE''d.
     For example:
          AH_VERBATIM([_GNU_SOURCE],
          [/* Enable GNU extensions on systems that have them.  */
          #ifndef _GNU_SOURCE
          # define _GNU_SOURCE
          #endif])
 - Macro: AH_TEMPLATE (KEY, DESCRIPTION)
     Tell `autoheader' to generate a template for KEY.  This macro
     generates standard templates just like `AC_DEFINE' when a
     DESCRIPTION is given.
     For example:
          AH_TEMPLATE([CRAY_STACKSEG_END],
                      [Define to one of _getb67, GETB67, getb67
                       for Cray-2 and Cray-YMP systems.  This
                       function is required for alloca.c support
                       on those systems.])
     will generate the following template, with the description properly
     justified.
          /* Define to one of _getb67, GETB67, getb67 for Cray-2 and
             Cray-YMP systems.  This function is required for alloca.c
             support on those systems.  */
          #undef CRAY_STACKSEG_END
 - Macro: AH_TOP (TEXT)
     Include TEXT at the top of the header template file.
 - Macro: AH_BOTTOM (TEXT)
     Include TEXT at the bottom of the header template file.