On 2009-10-02 14:45+0200 Hendrik Sattler wrote:
Zitat von Claudio Bley <b_l_...@ml1.net>:
But I think that his example is wrong, it should be:
set(a "-Lfoo -lbar")
message(STATUS "a = ${a}")
set(a_list ${a})
message(STATUS "a_list = ${a_list}")
Then the result should be
-- a = -Lfoo -lbar
-- a_list = -Lfoo;-lbar
No, should it not. How should that be possible? ${a} is not a list, it's
a string (ie. it does not contain semi colons).
The output is:
,----
| -- a = -Lfoo -lbar
| -- a_list = -Lfoo -lbar
`----
Then explain the detailed difference between the following three:
set(a_list -Lfoo -lbar) -> creates a list with "-Lfoo" and "-lbar"
set(a_list ${a}) -> ???
set(a_list "${a}") -> ???
Hi Hendrik:
Just in case you haven't done this for yourself yet, here are the results from
set(a "-Lfoo -lbar")
message(STATUS "a = ${a}")
set(a_list ${a})
message(STATUS "a_list = ${a_list}")
set(a_quoted_list "${a}")
message(STATUS "a_quoted_list = ${a_quoted_list}")
set(a_real_list -Lfoo -lbar)
message(STATUS "a_real_list = ${a_real_list}")
-- a = -Lfoo -lbar
-- a_list = -Lfoo -lbar
-- a_quoted_list = -Lfoo -lbar
-- a_real_list = -Lfoo;-lbar
So it makes absolutely no difference _in this context_ whether you quote ${a}
or not. The fourth example is just for completeness. I hope most here know
already from similar experiments that real CMake lists are equivalent to
semicolon-delimited strings.
As for your request to explain why the second and third results are
identical, I leave that to those who understand how and why CMake has been
implemented in the way it has. I am not in that group, which is why I always
fall back to simple experiments like above to determine CMake behaviour.
Alan
__________________________
Alan W. Irwin
Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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Linux-powered Science
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