On 11/11/2011 04:13 AM, Michael Hertling wrote:
On 11/10/2011 11:22 PM, Eric Noulard wrote:
If this is the case then it is a "GL/glxproto.h" design mistake
not CMake mistake.
Absolutely, try to compile the following program by hand; it's
the same the CHECK_INCLUDE_FILE() macro tries to compile, too:
#include<GL/glxproto.h>
int main(void){return 0;}
It will fail with the same error message, i.e. the GL/glxproto.h header
is not self-sufficient; if intentionally or accidentally, I don't know.
It's this failure that makes CHECK_INCLUDE_FILE() report the header as
non-existent, or better as "not compilable".
I just sent them an e-mail so that they will be aware of the issue.
This is true but the documentation tells you more about the macro
cmake --help-module CheckIncludeFile
says
"an optional third argument is the CFlags to add to the compile line or
you can use CMAKE_REQUIRED_FLAGS"
which clearly states that it does a compilation.
Indeed, CHECK_INCLUDE_FILE() means: Check if a header is *functional*.
Ok, will use find_file instead.
The thing you want is probably
if(DEFINED VARIABLE)
message(FATAL_ERROR "VARIABLE already defined :<${VARIABLE}> aborting")
endif()
Yeah, thanks.
I think it's not the responsability of check_include_file to do such job
but you can do that in your CMakeLists.txt
With FIND_FILE/PATH() looking for a header, the user must have the
possibility to make them no-ops by presetting the result variable,
so these functions must not overwrite a valid path. However, with
CHECK_INCLUDE_FILE(), the user can't "define" a header as working;
thus, there is no need to protect an already defined variable from
being overwritten, IMO. Moreover, the user must have the chance to
reuse the same variable for this purpose again without having the
configuration terminate. OTOH, one usually uses an individually
named variable for each header, e.g. HAVE_GL_GLXPROTO_H, as you
do, which is most certainly not reused for anything at all.
Ok but as I didn't understand why check_include_file was failing, I
tried many things like simple then double quoting GL/glxproto.h and also
tried a different variable name. I took HAVE_UNISTDE_H because I knew
HAVE_UNISTD_H was working. With HAVE_UNISTDE_H, check_include_file
seemed to work (it wasn't true, this variable name was simply defined
before elsewhere) so in the end, I believed some variable names were
allowed and others not. So to avoid the same mistake, I thought a
message (at least a STATUS one) wouldn't hurt.
IF("${VARIABLE}" MATCHES "^${VARIABLE}$") fails : is it intended ?
I do not understand
In which case does it fail?
Actually, every time.
Here is the beginning of my modified CheckIncludeFile.cmake :
MACRO(CHECK_INCLUDE_FILE INCLUDE VARIABLE)
message(STATUS "${VARIABLE}")
IF("${VARIABLE}" MATCHES "^${VARIABLE}$")
message(STATUS "${VARIABLE} matches ^${VARIABLE}$")
and I only have the following output
-- HAVE_SYS_TIME_H
-- HAVE_SYS_TYPES_H
-- HAVE_SYS_RESOURCE_H
-- HAVE_SYS_STAT_H
-- HAVE_UNISTD_H
-- HAVE_FCNTL_H
-- HAVE_GL_GLXPROTO_H
CMake Error at CMakeLists.txt:117 (message):
[..]
So the first IF is failing, skipping the whole macro.
If I add a # before this IF (and the corresponding ENDIF),
check_include_file does its jobs and even finds the other headers :
[...]
-- HAVE_FCNTL_H
-- HAVE_FCNTL_H matches ^HAVE_FCNTL_H$
-- Looking for fcntl.h
-- Looking for fcntl.h - found
-- HAVE_GL_GLXPROTO_H
-- HAVE_GL_GLXPROTO_H matches ^HAVE_GL_GLXPROTO_H$
-- Looking for GL/glxproto.h
-- Looking for GL/glxproto.h - not found
Any idea ?
--
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