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AX_HAVE_SELECT([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
AX_HAVE_PSELECT([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
This macro determines whether the system supports the select I/O event interface. A neat usage example would be:
AX_HAVE_SELECT( [AX_CONFIG_FEATURE_ENABLE(select)], [AX_CONFIG_FEATURE_DISABLE(select)]) AX_CONFIG_FEATURE( [select], [This platform supports select(7)], [HAVE_SELECT], [This platform supports select(7).])
Some systems also have the variant pselect(). The availability of that function can be tested with the second macro. Generally speaking, it is safe to assume that AX_HAVE_SELECT would succeed if AX_HAVE_SELECT_PWAIT has, but not the other way round.
Peter Simons <simons@cryp.to>
2008-05-01
AC_DEFUN([AX_HAVE_SELECT], [dnl AC_MSG_CHECKING([for select(2)]) AC_CACHE_VAL([ax_cv_have_select], [dnl AC_LINK_IFELSE([dnl AC_LANG_PROGRAM( [#include <sys/select.h>], [int rc; rc = select(0, (fd_set *)(0), (fd_set *)(0), (fd_set *)(0), (struct timeval *)(0));])], [ax_cv_have_select=yes], [ax_cv_have_select=no])]) AS_IF([test "${ax_cv_have_select}" = "yes"], [AC_MSG_RESULT([yes]) $1],[AC_MSG_RESULT([no]) $2]) ])dnl AC_DEFUN([AX_HAVE_PSELECT], [dnl AC_MSG_CHECKING([for pselect(2)]) AC_CACHE_VAL([ax_cv_have_pselect], [dnl AC_LINK_IFELSE([dnl AC_LANG_PROGRAM( [dnl #include <sys/select.h> #include <signal.h>], [dnl int rc; rc = select(0, (fd_set *)(0), (fd_set *)(0), (fd_set *)(0), (struct timeval *)(0)); rc = pselect(0, (fd_set *)(0), (fd_set *)(0), (fd_set *)(0), (struct timespec const *)(0), (sigset_t const *)(0));])], [ax_cv_have_pselect=yes], [ax_cv_have_pselect=no])]) AS_IF([test "${ax_cv_have_pselect}" = "yes"], [AC_MSG_RESULT([yes]) $1],[AC_MSG_RESULT([no]) $2]) ])dnl
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