dnl Copyright © 2014 Nick Bowler dnl dnl License WTFPL2: Do What The Fuck You Want To Public License, version 2. dnl This is free software: you are free to do what the fuck you want to. dnl There is NO WARRANTY, to the extent permitted by law. dnl DX_COMMAND_OUTPUT(variable, command, [action-if-ok], [action-if-failed]) dnl dnl Helper to capture standard output of a shell command. If the command dnl is successful then variable is assigned with its output (with newlines dnl converted to spaces), and action-if-ok is performed. Otherwise, if dnl the command is unsuccessful, then variable is not changed, and dnl action-if-failed is performed. AC_DEFUN([DX_COMMAND_OUTPUT], [AC_REQUIRE([_DX_COMMAND_OUTPUT_SETUP])dnl AS_IF([$2 >conftest.out 2>&AS_MESSAGE_LOG_FD], [m4_do([dx_fn_cmdout_collect_output $1], [m4_ifnblank([$3], [m4_newline([$3])])])], [$4]) rm -f conftest.out ]) AC_DEFUN_ONCE([_DX_COMMAND_OUTPUT_SETUP], [m4_divert_push([INIT_PREPARE])dnl # Helper function to store the contents of conftest.out into a shell variable. dx_fn_cmdout_collect_output () { AS_UNSET([$][1]) exec 3