6.2 Examining Syntax

To check for a syntax feature of the C, C++ or Fortran 77 compiler, such as whether it recognizes a certain keyword, use AC_TRY_COMPILE to try to compile a small program that uses that feature. You can also use it to check for structures and structure members that are not present on all systems.

Macro: AC_TRY_COMPILE (includes, function-body, [action-if-found], [action-if-not-found])

Create a C, C++ or Fortran 77 test program (depending on which language is current, see section 6.7 Language Choice), to see whether a function whose body consists of function-body can be compiled.

For C and C++, includes is any #include statements needed by the code in function-body (includes will be ignored if the currently selected language is Fortran 77). This macro also uses CFLAGS or CXXFLAGS if either C or C++ is the currently selected language, as well as CPPFLAGS, when compiling. If Fortran 77 is the currently selected language then FFLAGS will be used when compiling.

If the file compiles successfully, run shell commands action-if-found, otherwise run action-if-not-found.

This macro does not try to link; use AC_TRY_LINK if you need to do that (see section 6.3 Examining Libraries).