Next: , Previous: , Up: The Macros  


ax_patch_libtool_changing_cmds_ifs

Synopsis

AX_PATCH_LIBTOOL_CHANGING_CMDS_IFS

Description

Do a ‘grep "^[a-z]*_cmds=" libtool‘ - these are "subroutines" encoded by libtool.m4 into the generated libtool script. Since libtool assumes that there is no subroutine-facility in the shell invoked, these are not actually subroutines, but actually a "list of commands". This looks correct, but the command separator is not ";" - it is "~", the tilde character.

Now, grep again, look for ‘grep ’IFS="~"’ libtool‘ and see that libtool scripting uses a for-loop on the command-list, i.e for cmd in $some_cmds. This works correctly when the IFS was modified, where IFS stands for "input field separator" which is whitespace characters by default.

The problem: I have some real-world filesystems where there are directories using "~" inside of them, to be more to the point, it is a change control management software that uses source repositories of the form "path/master/project~version/src" and libtool has the tendency to resolve any symlinks so that it will paste such path into the $_cmds script when it gets evaluated a number of times.

This script is a workaround: I do not know why the ";" was not chosen as the IFS, perhaps it has some weird interactions in some shells since it is also the default record separator being one time bigger in context than the argument separator. I have made good success however with using "?" as the IFS, since there is no path-name that uses a question mark, and there is no _cmds ever around that uses "?" for some thing.

Oh yes, there are some usages of "*" to match shell-wise at the output file of some tool, so that might have triggered the choice to not use "?" in the first place - but in real life it never occured that a _cmds script was created that has gone to use "?". And so, this ac-macro exchanges the s/~/?/g in configured _cmds variables and replaces all occurences of s/IFS="~"/IFS="?"/ - and it all works smooth now.

Source Code

Download the latest version of ax_patch_libtool_changing_cmds_ifs.m4 or browse the macro’s revision history.

License

Copyright © 2008 Guido U. Draheim guidod@gmx.de

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

As a special exception, the respective Autoconf Macro’s copyright owner gives unlimited permission to copy, distribute and modify the configure scripts that are the output of Autoconf when processing the Macro. You need not follow the terms of the GNU General Public License when using or distributing such scripts, even though portions of the text of the Macro appear in them. The GNU General Public License (GPL) does govern all other use of the material that constitutes the Autoconf Macro.

This special exception to the GPL applies to versions of the Autoconf Macro released by the Autoconf Archive. When you make and distribute a modified version of the Autoconf Macro, you may extend this special exception to the GPL to apply to your modified version as well.


Next: , Previous: , Up: The Macros