Hi all,
I have a use case in which I would like to temporarily overwrite
standard CMake functions (e.g., add_library). After searching the
mailing list, I found that when a function is redefined, the original
function is still available but with an underscore prefix, e.g.,
function(add_library)
message("custom add_library")
_add_library(${ARGN})
endfunction()
The problem with this solution is that this in fact redefines
add_library permanently. My hope was that if I introduced some
additional scope, I would get the desired result:
function(testfun)
function(add_library)
message("custom add_library")
_add_library(${ARGN})
endfunction()
add_library(test SHARED IMPORTED)
endfunction()
testfun()
add_library(test2 SHARED IMPORTED)
As it turns out, this is not the case, and the second call to
add_library actually still calls my custom version, which is
unexpected and of course not what I want.
Under the assumption that only for the standard CMake functions the
underscore version would be created (I haven't found any official
documentation on this behavior), I then tried the following:
function(add_library)
message("custom add_library")
_add_library(${ARGN})
endfunction()
add_library(test SHARED IMPORTED)
function(add_library)
_add_library(${ARGN})
endfunction()
add_library(test2 SHARED IMPORTED)
This actually creates an infinite recursion loop and CMake crashes
with a segmentation fault. This means that the assumption was wrong,
and apparently all existing functions, upon redefinition, are renamed
to an underscore version (hence the infinite recursion).
Using this information, I was able to create the desired behavior in
the following way:
# Ensure that _add_library points to the original version
function(add_library)
endfunction()
# Ensure that __add_library points to the original version
function(_add_library)
endfunction(_add_library)
# Define the custom version
function(add_library)
message("custom add_library")
__add_library(${ARGN})
endfunction()
add_library(test SHARED IMPORTED)
# Restore the original implementation
function(add_library)
__add_library(${ARGN})
endfunction()
add_library(test2 SHARED IMPORTED)
This works, but looks a bit hackish, so I was wondering if there is
maybe a better, more elegant way to achieve the desired behavior?
Regards,
Yves
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