1package ExtUtils::Liblist; 2 3use strict; 4 5our $VERSION = '7.10_02'; 6 7use File::Spec; 8require ExtUtils::Liblist::Kid; 9our @ISA = qw(ExtUtils::Liblist::Kid File::Spec); 10 11# Backwards compatibility with old interface. 12sub ext { 13 goto &ExtUtils::Liblist::Kid::ext; 14} 15 16sub lsdir { 17 shift; 18 my $rex = qr/$_[1]/; 19 opendir DIR, $_[0]; 20 my @out = grep /$rex/, readdir DIR; 21 closedir DIR; 22 return @out; 23} 24 25__END__ 26 27=head1 NAME 28 29ExtUtils::Liblist - determine libraries to use and how to use them 30 31=head1 SYNOPSIS 32 33 require ExtUtils::Liblist; 34 35 $MM->ext($potential_libs, $verbose, $need_names); 36 37 # Usually you can get away with: 38 ExtUtils::Liblist->ext($potential_libs, $verbose, $need_names) 39 40=head1 DESCRIPTION 41 42This utility takes a list of libraries in the form C<-llib1 -llib2 43-llib3> and returns lines suitable for inclusion in an extension 44Makefile. Extra library paths may be included with the form 45C<-L/another/path> this will affect the searches for all subsequent 46libraries. 47 48It returns an array of four or five scalar values: EXTRALIBS, 49BSLOADLIBS, LDLOADLIBS, LD_RUN_PATH, and, optionally, a reference to 50the array of the filenames of actual libraries. Some of these don't 51mean anything unless on Unix. See the details about those platform 52specifics below. The list of the filenames is returned only if 53$need_names argument is true. 54 55Dependent libraries can be linked in one of three ways: 56 57=over 2 58 59=item * For static extensions 60 61by the ld command when the perl binary is linked with the extension 62library. See EXTRALIBS below. 63 64=item * For dynamic extensions at build/link time 65 66by the ld command when the shared object is built/linked. See 67LDLOADLIBS below. 68 69=item * For dynamic extensions at load time 70 71by the DynaLoader when the shared object is loaded. See BSLOADLIBS 72below. 73 74=back 75 76=head2 EXTRALIBS 77 78List of libraries that need to be linked with when linking a perl 79binary which includes this extension. Only those libraries that 80actually exist are included. These are written to a file and used 81when linking perl. 82 83=head2 LDLOADLIBS and LD_RUN_PATH 84 85List of those libraries which can or must be linked into the shared 86library when created using ld. These may be static or dynamic 87libraries. LD_RUN_PATH is a colon separated list of the directories 88in LDLOADLIBS. It is passed as an environment variable to the process 89that links the shared library. 90 91=head2 BSLOADLIBS 92 93List of those libraries that are needed but can be linked in 94dynamically at run time on this platform. SunOS/Solaris does not need 95this because ld records the information (from LDLOADLIBS) into the 96object file. This list is used to create a .bs (bootstrap) file. 97 98=head1 PORTABILITY 99 100This module deals with a lot of system dependencies and has quite a 101few architecture specific C<if>s in the code. 102 103=head2 VMS implementation 104 105The version of ext() which is executed under VMS differs from the 106Unix-OS/2 version in several respects: 107 108=over 2 109 110=item * 111 112Input library and path specifications are accepted with or without the 113C<-l> and C<-L> prefixes used by Unix linkers. If neither prefix is 114present, a token is considered a directory to search if it is in fact 115a directory, and a library to search for otherwise. Authors who wish 116their extensions to be portable to Unix or OS/2 should use the Unix 117prefixes, since the Unix-OS/2 version of ext() requires them. 118 119=item * 120 121Wherever possible, shareable images are preferred to object libraries, 122and object libraries to plain object files. In accordance with VMS 123naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl; 124it also looks for I<lib>lib and libI<lib> to accommodate Unix conventions 125used in some ported software. 126 127=item * 128 129For each library that is found, an appropriate directive for a linker options 130file is generated. The return values are space-separated strings of 131these directives, rather than elements used on the linker command line. 132 133=item * 134 135LDLOADLIBS contains both the libraries found based on C<$potential_libs> and 136the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those 137libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH 138are always empty. 139 140=back 141 142In addition, an attempt is made to recognize several common Unix library 143names, and filter them out or convert them to their VMS equivalents, as 144appropriate. 145 146In general, the VMS version of ext() should properly handle input from 147extensions originally designed for a Unix or VMS environment. If you 148encounter problems, or discover cases where the search could be improved, 149please let us know. 150 151=head2 Win32 implementation 152 153The version of ext() which is executed under Win32 differs from the 154Unix-OS/2 version in several respects: 155 156=over 2 157 158=item * 159 160If C<$potential_libs> is empty, the return value will be empty. 161Otherwise, the libraries specified by C<$Config{perllibs}> (see Config.pm) 162will be appended to the list of C<$potential_libs>. The libraries 163will be searched for in the directories specified in C<$potential_libs>, 164C<$Config{libpth}>, and in C<$Config{installarchlib}/CORE>. 165For each library that is found, a space-separated list of fully qualified 166library pathnames is generated. 167 168=item * 169 170Input library and path specifications are accepted with or without the 171C<-l> and C<-L> prefixes used by Unix linkers. 172 173An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look 174for the libraries that follow. 175 176An entry of the form C<-lfoo> specifies the library C<foo>, which may be 177spelled differently depending on what kind of compiler you are using. If 178you are using GCC, it gets translated to C<libfoo.a>, but for other win32 179compilers, it becomes C<foo.lib>. If no files are found by those translated 180names, one more attempt is made to find them using either C<foo.a> or 181C<libfoo.lib>, depending on whether GCC or some other win32 compiler is 182being used, respectively. 183 184If neither the C<-L> or C<-l> prefix is present in an entry, the entry is 185considered a directory to search if it is in fact a directory, and a 186library to search for otherwise. The C<$Config{lib_ext}> suffix will 187be appended to any entries that are not directories and don't already have 188the suffix. 189 190Note that the C<-L> and C<-l> prefixes are B<not required>, but authors 191who wish their extensions to be portable to Unix or OS/2 should use the 192prefixes, since the Unix-OS/2 version of ext() requires them. 193 194=item * 195 196Entries cannot be plain object files, as many Win32 compilers will 197not handle object files in the place of libraries. 198 199=item * 200 201Entries in C<$potential_libs> beginning with a colon and followed by 202alphanumeric characters are treated as flags. Unknown flags will be ignored. 203 204An entry that matches C</:nodefault/i> disables the appending of default 205libraries found in C<$Config{perllibs}> (this should be only needed very rarely). 206 207An entry that matches C</:nosearch/i> disables all searching for 208the libraries specified after it. Translation of C<-Lfoo> and 209C<-lfoo> still happens as appropriate (depending on compiler being used, 210as reflected by C<$Config{cc}>), but the entries are not verified to be 211valid files or directories. 212 213An entry that matches C</:search/i> reenables searching for 214the libraries specified after it. You can put it at the end to 215enable searching for default libraries specified by C<$Config{perllibs}>. 216 217=item * 218 219The libraries specified may be a mixture of static libraries and 220import libraries (to link with DLLs). Since both kinds are used 221pretty transparently on the Win32 platform, we do not attempt to 222distinguish between them. 223 224=item * 225 226LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS 227and LD_RUN_PATH are always empty (this may change in future). 228 229=item * 230 231You must make sure that any paths and path components are properly 232surrounded with double-quotes if they contain spaces. For example, 233C<$potential_libs> could be (literally): 234 235 "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib" 236 237Note how the first and last entries are protected by quotes in order 238to protect the spaces. 239 240=item * 241 242Since this module is most often used only indirectly from extension 243C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add 244a library to the build process for an extension: 245 246 LIBS => ['-lgl'] 247 248When using GCC, that entry specifies that MakeMaker should first look 249for C<libgl.a> (followed by C<gl.a>) in all the locations specified by 250C<$Config{libpth}>. 251 252When using a compiler other than GCC, the above entry will search for 253C<gl.lib> (followed by C<libgl.lib>). 254 255If the library happens to be in a location not in C<$Config{libpth}>, 256you need: 257 258 LIBS => ['-Lc:\gllibs -lgl'] 259 260Here is a less often used example: 261 262 LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32'] 263 264This specifies a search for library C<gl> as before. If that search 265fails to find the library, it looks at the next item in the list. The 266C<:nosearch> flag will prevent searching for the libraries that follow, 267so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>, 268since GCC can use that value as is with its linker. 269 270When using the Visual C compiler, the second item is returned as 271C<-libpath:d:\mesalibs mesa.lib user32.lib>. 272 273When using the Borland compiler, the second item is returned as 274C<-Ld:\mesalibs mesa.lib user32.lib>, and MakeMaker takes care of 275moving the C<-Ld:\mesalibs> to the correct place in the linker 276command line. 277 278=back 279 280 281=head1 SEE ALSO 282 283L<ExtUtils::MakeMaker> 284 285=cut 286 287