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CMake: check that the POSIX regex functions link, not just regex.h #67

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CMake: check that the POSIX regex functions link, not just regex.h #67

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47 changes: 45 additions & 2 deletions CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -141,8 +141,50 @@ if(PCRE)
message(WARNING "PCRE was requested, but is not available")
endif()
endif()
# regcomp() and friends are in libc on glibc, macOS and the BSDs, but on some
# systems regex.h belongs to a separate library that is not linked by default
# (e.g. libsystre/libtre on MSYS2, libgnurx on MinGW). The header alone is not
# enough to link, so confirm the functions are linkable and record the extra
# library when one is required; otherwise fall back to GKlib's own regex
# implementation (gkregex), which is also used when GKREGEX is set. The test
# calls the functions rather than using check_symbol_exists(), which accepts a
# macro, and TRE's regex.h defines regcomp etc. as macros for tre_regcomp etc.
set(REGEX_LIBRARY "")
set(GKLIB_REGEX_TEST_SOURCE "
#include <stddef.h>
#include <regex.h>
int main(void) {
regex_t re; regmatch_t m[1]; char buf[8]; int rc;
rc = regcomp(&re, \"a\", REG_EXTENDED);
if (rc != 0) return (int)regerror(rc, &re, buf, sizeof(buf));
rc = regexec(&re, \"a\", 1, m, 0);
regfree(&re);
return rc;
}")
if(NOT HAVE_PCREPOSIX_H)
check_include_file(regex.h HAVE_REGEX_H)
if(GKREGEX)
set(HAVE_REGEX_H FALSE)
else()
check_include_file(regex.h HAVE_REGEX_H)
endif()
if(HAVE_REGEX_H)
check_c_source_compiles("${GKLIB_REGEX_TEST_SOURCE}" GKLIB_REGEX_IN_LIBC)
if(NOT GKLIB_REGEX_IN_LIBC)
foreach(lib systre tre gnurx regex)
set(CMAKE_REQUIRED_LIBRARIES ${lib})
check_c_source_compiles("${GKLIB_REGEX_TEST_SOURCE}"
GKLIB_REGEX_IN_LIB${lib})
unset(CMAKE_REQUIRED_LIBRARIES)
if(GKLIB_REGEX_IN_LIB${lib})
set(REGEX_LIBRARY ${lib})
break()
endif()
endforeach()
if(NOT REGEX_LIBRARY)
set(HAVE_REGEX_H FALSE)
endif()
endif()
endif()
if(NOT HAVE_REGEX_H)
set(USE_GKREGEX ON)
endif()
Expand Down Expand Up @@ -207,7 +249,8 @@ target_compile_options(${PROJECT_NAME}

target_link_libraries(${PROJECT_NAME}
PUBLIC $<$<BOOL:${OpenMP_C_FOUND}>:OpenMP::OpenMP_C>
${EXECINFO_LIBRARY})
${EXECINFO_LIBRARY}
${REGEX_LIBRARY})

#-------------------------------------------------------------------------------
# APPS configuration
Expand Down