1package ExtUtils::Liblist; 2 3use strict; 4 5our $VERSION = '7.34'; 6$VERSION = eval $VERSION; 7 8use File::Spec; 9require ExtUtils::Liblist::Kid; 10our @ISA = qw(ExtUtils::Liblist::Kid File::Spec); 11 12# Backwards compatibility with old interface. 13sub ext { 14 goto &ExtUtils::Liblist::Kid::ext; 15} 16 17sub lsdir { 18 shift; 19 my $rex = qr/$_[1]/; 20 opendir my $dir_fh, $_[0]; 21 my @out = grep /$rex/, readdir $dir_fh; 22 closedir $dir_fh; 23 return @out; 24} 25 26__END__ 27 28=head1 NAME 29 30ExtUtils::Liblist - determine libraries to use and how to use them 31 32=head1 SYNOPSIS 33 34 require ExtUtils::Liblist; 35 36 $MM->ext($potential_libs, $verbose, $need_names); 37 38 # Usually you can get away with: 39 ExtUtils::Liblist->ext($potential_libs, $verbose, $need_names) 40 41=head1 DESCRIPTION 42 43This utility takes a list of libraries in the form C<-llib1 -llib2 44-llib3> and returns lines suitable for inclusion in an extension 45Makefile. Extra library paths may be included with the form 46C<-L/another/path> this will affect the searches for all subsequent 47libraries. 48 49It returns an array of four or five scalar values: EXTRALIBS, 50BSLOADLIBS, LDLOADLIBS, LD_RUN_PATH, and, optionally, a reference to 51the array of the filenames of actual libraries. Some of these don't 52mean anything unless on Unix. See the details about those platform 53specifics below. The list of the filenames is returned only if 54$need_names argument is true. 55 56Dependent libraries can be linked in one of three ways: 57 58=over 2 59 60=item * For static extensions 61 62by the ld command when the perl binary is linked with the extension 63library. See EXTRALIBS below. 64 65=item * For dynamic extensions at build/link time 66 67by the ld command when the shared object is built/linked. See 68LDLOADLIBS below. 69 70=item * For dynamic extensions at load time 71 72by the DynaLoader when the shared object is loaded. See BSLOADLIBS 73below. 74 75=back 76 77=head2 EXTRALIBS 78 79List of libraries that need to be linked with when linking a perl 80binary which includes this extension. Only those libraries that 81actually exist are included. These are written to a file and used 82when linking perl. 83 84=head2 LDLOADLIBS and LD_RUN_PATH 85 86List of those libraries which can or must be linked into the shared 87library when created using ld. These may be static or dynamic 88libraries. LD_RUN_PATH is a colon separated list of the directories 89in LDLOADLIBS. It is passed as an environment variable to the process 90that links the shared library. 91 92=head2 BSLOADLIBS 93 94List of those libraries that are needed but can be linked in 95dynamically at run time on this platform. SunOS/Solaris does not need 96this because ld records the information (from LDLOADLIBS) into the 97object file. This list is used to create a .bs (bootstrap) file. 98 99=head1 PORTABILITY 100 101This module deals with a lot of system dependencies and has quite a 102few architecture specific C<if>s in the code. 103 104=head2 VMS implementation 105 106The version of ext() which is executed under VMS differs from the 107Unix-OS/2 version in several respects: 108 109=over 2 110 111=item * 112 113Input library and path specifications are accepted with or without the 114C<-l> and C<-L> prefixes used by Unix linkers. If neither prefix is 115present, a token is considered a directory to search if it is in fact 116a directory, and a library to search for otherwise. Authors who wish 117their extensions to be portable to Unix or OS/2 should use the Unix 118prefixes, since the Unix-OS/2 version of ext() requires them. 119 120=item * 121 122Wherever possible, shareable images are preferred to object libraries, 123and object libraries to plain object files. In accordance with VMS 124naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl; 125it also looks for I<lib>lib and libI<lib> to accommodate Unix conventions 126used in some ported software. 127 128=item * 129 130For each library that is found, an appropriate directive for a linker options 131file is generated. The return values are space-separated strings of 132these directives, rather than elements used on the linker command line. 133 134=item * 135 136LDLOADLIBS contains both the libraries found based on C<$potential_libs> and 137the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those 138libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH 139are always empty. 140 141=back 142 143In addition, an attempt is made to recognize several common Unix library 144names, and filter them out or convert them to their VMS equivalents, as 145appropriate. 146 147In general, the VMS version of ext() should properly handle input from 148extensions originally designed for a Unix or VMS environment. If you 149encounter problems, or discover cases where the search could be improved, 150please let us know. 151 152=head2 Win32 implementation 153 154The version of ext() which is executed under Win32 differs from the 155Unix-OS/2 version in several respects: 156 157=over 2 158 159=item * 160 161If C<$potential_libs> is empty, the return value will be empty. 162Otherwise, the libraries specified by C<$Config{perllibs}> (see Config.pm) 163will be appended to the list of C<$potential_libs>. The libraries 164will be searched for in the directories specified in C<$potential_libs>, 165C<$Config{libpth}>, and in C<$Config{installarchlib}/CORE>. 166For each library that is found, a space-separated list of fully qualified 167library pathnames is generated. 168 169=item * 170 171Input library and path specifications are accepted with or without the 172C<-l> and C<-L> prefixes used by Unix linkers. 173 174An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look 175for the libraries that follow. 176 177An entry of the form C<-lfoo> specifies the library C<foo>, which may be 178spelled differently depending on what kind of compiler you are using. If 179you are using GCC, it gets translated to C<libfoo.a>, but for other win32 180compilers, it becomes C<foo.lib>. If no files are found by those translated 181names, one more attempt is made to find them using either C<foo.a> or 182C<libfoo.lib>, depending on whether GCC or some other win32 compiler is 183being used, respectively. 184 185If neither the C<-L> or C<-l> prefix is present in an entry, the entry is 186considered a directory to search if it is in fact a directory, and a 187library to search for otherwise. The C<$Config{lib_ext}> suffix will 188be appended to any entries that are not directories and don't already have 189the suffix. 190 191Note that the C<-L> and C<-l> prefixes are B<not required>, but authors 192who wish their extensions to be portable to Unix or OS/2 should use the 193prefixes, since the Unix-OS/2 version of ext() requires them. 194 195=item * 196 197Entries cannot be plain object files, as many Win32 compilers will 198not handle object files in the place of libraries. 199 200=item * 201 202Entries in C<$potential_libs> beginning with a colon and followed by 203alphanumeric characters are treated as flags. Unknown flags will be ignored. 204 205An entry that matches C</:nodefault/i> disables the appending of default 206libraries found in C<$Config{perllibs}> (this should be only needed very rarely). 207 208An entry that matches C</:nosearch/i> disables all searching for 209the libraries specified after it. Translation of C<-Lfoo> and 210C<-lfoo> still happens as appropriate (depending on compiler being used, 211as reflected by C<$Config{cc}>), but the entries are not verified to be 212valid files or directories. 213 214An entry that matches C</:search/i> reenables searching for 215the libraries specified after it. You can put it at the end to 216enable searching for default libraries specified by C<$Config{perllibs}>. 217 218=item * 219 220The libraries specified may be a mixture of static libraries and 221import libraries (to link with DLLs). Since both kinds are used 222pretty transparently on the Win32 platform, we do not attempt to 223distinguish between them. 224 225=item * 226 227LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS 228and LD_RUN_PATH are always empty (this may change in future). 229 230=item * 231 232You must make sure that any paths and path components are properly 233surrounded with double-quotes if they contain spaces. For example, 234C<$potential_libs> could be (literally): 235 236 "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib" 237 238Note how the first and last entries are protected by quotes in order 239to protect the spaces. 240 241=item * 242 243Since this module is most often used only indirectly from extension 244C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add 245a library to the build process for an extension: 246 247 LIBS => ['-lgl'] 248 249When using GCC, that entry specifies that MakeMaker should first look 250for C<libgl.a> (followed by C<gl.a>) in all the locations specified by 251C<$Config{libpth}>. 252 253When using a compiler other than GCC, the above entry will search for 254C<gl.lib> (followed by C<libgl.lib>). 255 256If the library happens to be in a location not in C<$Config{libpth}>, 257you need: 258 259 LIBS => ['-Lc:\gllibs -lgl'] 260 261Here is a less often used example: 262 263 LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32'] 264 265This specifies a search for library C<gl> as before. If that search 266fails to find the library, it looks at the next item in the list. The 267C<:nosearch> flag will prevent searching for the libraries that follow, 268so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>, 269since GCC can use that value as is with its linker. 270 271When using the Visual C compiler, the second item is returned as 272C<-libpath:d:\mesalibs mesa.lib user32.lib>. 273 274When using the Borland compiler, the second item is returned as 275C<-Ld:\mesalibs mesa.lib user32.lib>, and MakeMaker takes care of 276moving the C<-Ld:\mesalibs> to the correct place in the linker 277command line. 278 279=back 280 281 282=head1 SEE ALSO 283 284L<ExtUtils::MakeMaker> 285 286=cut 287 288