readline issue

Paul Guyot pguyot at
Sat Apr 7 21:14:42 PDT 2007

Hi folks,

We cannot simply autoconf for readline for the following reasons:
(a) readline comes with two incompatible APIs.
(b) Apple's gcc reads /usr/local/include before /usr/include
(c) Apple's ld reads /usr/lib/libreadline.dylib before /usr/local/lib/ 
libreadline.a when provided with -L/usr/local/lib
(d) some users have an incompatible version of readline in /usr/local.

In other words, if you install the incompatible version of readline  
available in ticket 10651 in /usr/local, I think you cannot compile  
*and* link the following piece of code without redefining completely  
the list of system includes, with -nostdinc. Which is the beginning  
of a nightmare.

#include <stdio.h>
# include <readline/readline.h>
int main(void) {
	void* ptr = (void*) rl_username_completion_function;
	return 0;

or this one:

#include <stdio.h>
# include <readline/readline.h>
int main(void) {
	void* ptr = (void*) username_completion_function;
	return 0;

I think it's time to wonder why we autoconf for readline (and other  
stuff). At some point we decided that MacPorts (then darwinports) was  
to support MacOS X only. (I was against this decision, but here we  
are today; and considering that I no longer can install MacPorts on  
linux boxes I have access to, I would favor the use or more MacOS X  
technologies). Should we simply drop the autoconf options for  
readline? Should we just determine what's the API version of readline  
installed in /usr/? Should we keep users whining they cannot install  
MacPorts because they have a readline in /usr/local?

Vincent: before you comment on this, I must say that I am not taking  
into consideration the C*_PATH and LIBRARY_PATH problem. In fact, I  
do not care about it at all, I am concerned by end-users not people  
with a Ph.D. in computer science who are wise enough to know that if  
they set these variables, it might break things and they need to  
unset them before compiling base/ :)


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