ld/ld.1

   1 .\" Copyright (c) 1991, 92, 93, 94, 95, 1996 Free Software Foundation
   2 .\" See section COPYING for conditions for redistribution
   3 .TH ld 1 "17 August 1992" "cygnus support" "GNU Development Tools"
   4 .de BP
   5 .sp
   6 .ti \-.2i
   7 \(**
   8 ..
   9
  10 .SH NAME
  11 ld \- the GNU linker
  12
  13 .SH SYNOPSIS
  14 .hy 0
  15 .na
  16 .TP
  17 .B ld
  18 .RB "[\|" \-o "
  19 .I output\c
  20 \&\|] \c
  21 .I objfile\c
  22 \&.\|.\|.
  23 .br
  24 .RB "[\|" \-A\c
  25 .I architecture\c
  26 \&\|]
  27 .RB "[\|" "\-b\ "\c
  28 .I input-format\c
  29 \&\|]
  30 .RB "[\|" \-Bstatic "\|]"
  31 .RB "[\|" \-Bdynamic "\|]"
  32 .RB "[\|" \-Bsymbolic "\|]"
  33 .RB "[\|" "\-c\ "\c
  34 .I commandfile\c
  35 \&\|]
  36 .RB "[\|" \-d | \-dc | \-dp\c
  37 \|]
  38 .br
  39 .RB "[\|" "\-defsym\ "\c
  40 .I symbol\c
  41 \& = \c
  42 .I expression\c
  43 \&\|]
  44 .RB "[\|" "\-e\ "\c
  45 .I entry\c
  46 \&\|]
  47 .RB "[\|" \-embedded\-relocs "\|]"
  48 .RB "[\|" \-export\-dynamic "\|]"
  49 .RB "[\|" \-F "\|]"
  50 .RB "[\|" "\-F\ "\c
  51 .I format\c
  52 \&\|]
  53 .RB "[\|" "\-format\ "\c
  54 .I input-format\c
  55 \&\|]
  56 .RB "[\|" \-g "\|]"
  57 .RB "[\|" \-G
  58 .I size\c
  59 \&\|]
  60 .RB "[\|" \-\-help "\|]"
  61 .RB "[\|" \-i "\|]"
  62 .RB "[\|" \-l\c
  63 .I ar\c
  64 \&\|]
  65 .RB "[\|" \-L\c
  66 .I searchdir\c
  67 \&\|]
  68 .RB "[\|" \-M "\|]"
  69 .RB "[\|" \-Map
  70 .I mapfile\c
  71 \&\|]
  72 .RB "[\|" \-m
  73 .I emulation\c
  74 \&\|]
  75 .RB "[\|" \-n | \-N "\|]"
  76 .RB "[\|" \-noinhibit-exec "\|]"
  77 .RB "[\|" \-no\-keep\-memory "\|]"
  78 .RB "[\|" "\-oformat\ "\c
  79 .I output-format\c
  80 \&\|]
  81 .RB "[\|" "\-R\ "\c
  82 .I filename\c
  83 \&\|]
  84 .RB "[\|" \-relax "\|]"
  85 .RB "[\|" \-r | \-Ur "\|]"
  86 .RB "[\|" "\-rpath\ "\c
  87 .I directory\c
  88 \&\|]
  89 .RB "[\|" "\-rpath\-link\ "\c
  90 .I directory\c
  91 \&\|]
  92 .RB "[\|" \-S "\|]"
  93 .RB "[\|" \-s "\|]"
  94 .RB "[\|" \-shared "\|]"
  95 .RB "[\|" \-sort\-common "\|]"
  96 .RB "[\|" "\-split\-by\-reloc\ "\c
  97 .I count\c
  98 \&\|]
  99 .RB "[\|" \-split\-by\-file "\|]"
 100 .RB "[\|" "\-T\ "\c
 101 .I commandfile\c
 102 \&\|]
 103 .RB "[\|" "\-Ttext\ "\c
 104 .I textorg\c
 105 \&\|]
 106 .RB "[\|" "\-Tdata\ "\c
 107 .I dataorg\c
 108 \&\|]
 109 .RB "[\|" "\-Tbss\ "\c
 110 .I bssorg\c
 111 \&\|]
 112 .RB "[\|" \-t "\|]"
 113 .RB "[\|" "\-u\ "\c
 114 .I sym\c
 115 \&]
 116 .RB "[\|" \-V "\|]"
 117 .RB "[\|" \-v "\|]"
 118 .RB "[\|" \-\-verbose "\|]"
 119 .RB "[\|" \-\-version "\|]"
 120 .RB "[\|" \-warn\-common "\|]"
 121 .RB "[\|" \-warn\-constructors "\|]"
 122 .RB "[\|" \-warn\-multiple\-gp "\|]"
 123 .RB "[\|" \-warn\-once "\|]"
 124 .RB "[\|" \-\-whole\-archive "\|]"
 125 .RB "[\|" \-\-no\-whole\-archive "\|]"
 126 .RB "[\|" \-X "\|]"
 127 .RB "[\|" \-x "\|]"
 128 .ad b
 129 .hy 1
 130 .SH DESCRIPTION
 131 \c
 132 .B ld\c
 133 \& combines a number of object and archive files, relocates
 134 their data and ties up symbol references. Often the last step in
 135 building a new compiled program to run is a call to \c
 136 .B ld\c
 137 \&.
 138
 139 \c
 140 .B ld\c
 141 \& accepts Linker Command Language files
 142 to provide explicit and total control over the linking process.
 143 This man page does not describe the command language; see the `\|\c
 144 .B ld\c
 145 \|' entry in `\|\c
 146 .B info\c
 147 \|', or the manual
 148 .I
 149 ld: the GNU linker
 150 \&, for full details on the command language and on other aspects of
 151 the GNU linker.
 152
 153 This version of \c
 154 .B ld\c
 155 \& uses the general purpose BFD libraries
 156 to operate on object files. This allows \c
 157 .B ld\c
 158 \& to read, combine, and
 159 write object files in many different formats\(em\&for example, COFF or
 160 \c
 161 .B a.out\c
 162 \&.  Different formats may be linked together to produce any
 163 available kind of object file.  You can use `\|\c
 164 .B objdump \-i\c
 165 \|' to get a list of formats supported on various architectures; see
 166 .BR objdump ( 1 ).
 167
 168 Aside from its flexibility, the GNU linker is more helpful than other
 169 linkers in providing diagnostic information.  Many linkers abandon
 170 execution immediately upon encountering an error; whenever possible,
 171 \c
 172 .B ld\c
 173 \& continues executing, allowing you to identify other errors
 174 (or, in some cases, to get an output file in spite of the error).
 175
 176 The GNU linker \c
 177 .B ld\c
 178 \& is meant to cover a broad range of situations,
 179 and to be as compatible as possible with other linkers.  As a result,
 180 you have many choices to control its behavior through the command line,
 181 and through environment variables.
 182
 183 .SH OPTIONS
 184 The plethora of command-line options may seem intimidating, but in
 185 actual practice few of them are used in any particular context.
 186 For instance, a frequent use of \c
 187 .B ld\c
 188 \& is to link standard Unix
 189 object files on a standard, supported Unix system.  On such a system, to
 190 link a file \c
 191 .B hello.o\c
 192 \&:
 193 .sp
 194 .br
 195 $\ ld\ \-o\ output\ /lib/crt0.o\ hello.o\ \-lc
 196 .br
 197 .sp
 198 This tells \c
 199 .B ld\c
 200 \& to produce a file called \c
 201 .B output\c
 202 \& as the
 203 result of linking the file \c
 204 .B /lib/crt0.o\c
 205 \& with \c
 206 .B hello.o\c
 207 \& and
 208 the library \c
 209 .B libc.a\c
 210 \& which will come from the standard search
 211 directories.
 212
 213 The command-line options to \c
 214 .B ld\c
 215 \& may be specified in any order, and
 216 may be repeated at will.  For the most part, repeating an option with a
 217 different argument will either have no further effect, or override prior
 218 occurrences (those further to the left on the command line) of an
 219 option.
 220
 221 The exceptions\(em\&which may meaningfully be used more than once\(em\&are
 222 \c
 223 .B \-A\c
 224 \&, \c
 225 .B \-b\c
 226 \& (or its synonym \c
 227 .B \-format\c
 228 \&), \c
 229 .B \-defsym\c
 230 \&,
 231 \c
 232 .B \-L\c
 233 \&, \c
 234 .B \-l\c
 235 \&, \c
 236 .B \-R\c
 237 \&, and \c
 238 .B \-u\c
 239 \&.
 240
 241 The list of object files to be linked together, shown as \c
 242 .I objfile\c
 243 \&,
 244 may follow, precede, or be mixed in with command-line options; save that
 245 an \c
 246 .I objfile\c
 247 \& argument may not be placed between an option flag and
 248 its argument.
 249
 250 Usually the linker is invoked with at least one object file, but other
 251 forms of binary input files can also be specified with \c
 252 .B \-l\c
 253 \&,
 254 \c
 255 .B \-R\c
 256 \&, and the script command language.  If \c
 257 .I no\c
 258 \& binary input
 259 files at all are specified, the linker does not produce any output, and
 260 issues the message `\|\c
 261 .B No input files\c
 262 \|'.
 263
 264 Option arguments must either follow the option letter without intervening
 265 whitespace, or be given as separate arguments immediately following the
 266 option that requires them.
 267
 268 .TP
 269 .BI "-A" "architecture"
 270 In the current release of \c
 271 .B ld\c
 272 \&, this option is useful only for the
 273 Intel 960 family of architectures.  In that \c
 274 .B ld\c
 275 \& configuration, the
 276 \c
 277 .I architecture\c
 278 \& argument is one of the two-letter names identifying
 279 members of the 960 family; the option specifies the desired output
 280 target, and warns of any incompatible instructions in the input files.
 281 It also modifies the linker's search strategy for archive libraries, to
 282 support the use of libraries specific to each particular
 283 architecture, by including in the search loop names suffixed with the
 284 string identifying the architecture.
 285
 286 For example, if your \c
 287 .B ld\c
 288 \& command line included `\|\c
 289 .B \-ACA\c
 290 \|' as
 291 well as `\|\c
 292 .B \-ltry\c
 293 \|', the linker would look (in its built-in search
 294 paths, and in any paths you specify with \c
 295 .B \-L\c
 296 \&) for a library with
 297 the names
 298 .sp
 299 .br
 300 try
 301 .br
 302 libtry.a
 303 .br
 304 tryca
 305 .br
 306 libtryca.a
 307 .br
 308 .sp
 309
 310 The first two possibilities would be considered in any event; the last
 311 two are due to the use of `\|\c
 312 .B \-ACA\c
 313 \|'.
 314
 315 Future releases of \c
 316 .B ld\c
 317 \& may support similar functionality for
 318 other architecture families.
 319
 320 You can meaningfully use \c
 321 .B \-A\c
 322 \& more than once on a command line, if
 323 an architecture family allows combination of target architectures; each
 324 use will add another pair of name variants to search for when \c
 325 .B \-l
 326 specifies a library.
 327
 328 .TP
 329 .BI "\-b " "input-format"
 330 Specify the binary format for input object files that follow this option
 331 on the command line.  You don't usually need to specify this, as
 332 \c
 333 .B ld\c
 334 \& is configured to expect as a default input format the most
 335 usual format on each machine.  \c
 336 .I input-format\c
 337 \& is a text string, the
 338 name of a particular format supported by the BFD libraries.
 339 \c
 340 .B \-format \c
 341 .I input-format\c
 342 \&\c
 343 \& has the same effect, as does the script command
 344 .BR TARGET .
 345
 346 You may want to use this option if you are linking files with an unusual
 347 binary format.  You can also use \c
 348 .B \-b\c
 349 \& to switch formats explicitly (when
 350 linking object files of different formats), by including
 351 \c
 352 .B \-b \c
 353 .I input-format\c
 354 \&\c
 355 \& before each group of object files in a
 356 particular format.
 357
 358 The default format is taken from the environment variable
 359 .B GNUTARGET\c
 360 \&.  You can also define the input
 361 format from a script, using the command \c
 362 .B TARGET\c
 363 \&.
 364
 365 .TP
 366 .B \-Bstatic
 367 Do not link against shared libraries.  This is only meaningful on
 368 platforms for which shared libraries are supported.
 369
 370 .TP
 371 .B \-Bdynamic
 372 Link against dynamic libraries.  This is only meaningful on platforms
 373 for which shared libraries are supported.  This option is normally the
 374 default on such platforms.
 375
 376 .TP
 377 .B \-Bsymbolic
 378 When creating a shared library, bind references to global symbols to
 379 the definition within the shared library, if any.  Normally, it is
 380 possible for a program linked against a shared library to override the
 381 definition within the shared library.  This option is only meaningful
 382 on ELF platforms which support shared libraries.
 383
 384 .TP
 385 .BI "\-c " "commandfile"
 386 Directs \c
 387 .B ld\c
 388 \& to read link commands from the file
 389 \c
 390 .I commandfile\c
 391 \&.  These commands will completely override \c
 392 .B ld\c
 393 \&'s
 394 default link format (rather than adding to it); \c
 395 .I commandfile\c
 396 \& must
 397 specify everything necessary to describe the target format.
 398
 399
 400 You may also include a script of link commands directly in the command
 401 line by bracketing it between `\|\c
 402 .B {\c
 403 \|' and `\|\c
 404 .B }\c
 405 \|' characters.
 406
 407 .TP
 408 .B \-d
 409 .TP
 410 .B \-dc
 411 .TP
 412 .B \-dp
 413 These three options are equivalent; multiple forms are supported for
 414 compatibility with other linkers.  Use any of them to make \c
 415 .B ld
 416 assign space to common symbols even if a relocatable output file is
 417 specified (\c
 418 .B \-r\c
 419 \&).  The script command
 420 \c
 421 .B FORCE_COMMON_ALLOCATION\c
 422 \& has the same effect.
 423
 424 .TP
 425 .BI "-defsym " "symbol" "\fR = \fP" expression
 426 Create a global symbol in the output file, containing the absolute
 427 address given by \c
 428 .I expression\c
 429 \&.  You may use this option as many
 430 times as necessary to define multiple symbols in the command line.  A
 431 limited form of arithmetic is supported for the \c
 432 .I expression\c
 433 \& in this
 434 context: you may give a hexadecimal constant or the name of an existing
 435 symbol, or use \c
 436 .B +\c
 437 \& and \c
 438 .B \-\c
 439 \& to add or subtract hexadecimal
 440 constants or symbols.  If you need more elaborate expressions, consider
 441 using the linker command language from a script.
 442
 443 .TP
 444 .BI "-e " "entry"\c
 445 \&
 446 Use \c
 447 .I entry\c
 448 \& as the explicit symbol for beginning execution of your
 449 program, rather than the default entry point.  for a
 450 discussion of defaults and other ways of specifying the
 451 entry point.
 452
 453 .TP
 454 .B \-embedded\-relocs
 455 This option is only meaningful when linking MIPS embedded PIC code,
 456 generated by the
 457 .B \-membedded\-pic
 458 option to the GNU compiler and assembler.  It causes the linker to
 459 create a table which may be used at runtime to relocate any data which
 460 was statically initialized to pointer values.  See the code in
 461 testsuite/ld-empic for details.
 462
 463 .TP
 464 .B \-export\-dynamic
 465 When creating an ELF file, add all symbols to the dynamic symbol table.
 466 Normally, the dynamic symbol table contains only symbols which are used
 467 by a dynamic object.  This option is needed for some uses of
 468 .I dlopen.
 469
 470 .TP
 471 .B \-F
 472 .TP
 473 .BI "-F" "format"
 474 Some older linkers used this option throughout a compilation toolchain
 475 for specifying object-file format for both input and output object
 476 files.  \c
 477 .B ld\c
 478 \&'s mechanisms (the \c
 479 .B \-b\c
 480 \& or \c
 481 .B \-format\c
 482 \& options
 483 for input files, the \c
 484 .B TARGET\c
 485 \& command in linker scripts for output
 486 files, the \c
 487 .B GNUTARGET\c
 488 \& environment variable) are more flexible, but
 489 but it accepts (and ignores) the \c
 490 .B \-F\c
 491 \& option flag for compatibility
 492 with scripts written to call the old linker.
 493
 494 .TP
 495 .BI "\-format " "input\-format"
 496 Synonym for \c
 497 .B \-b\c
 498 \& \c
 499 .I input\-format\c
 500 \&.
 501
 502 .TP
 503 .B \-g
 504 Accepted, but ignored; provided for compatibility with other tools.
 505
 506 .TP
 507 .BI "\-G " "size"\c
 508 Set the maximum size of objects to be optimized using the GP register
 509 to
 510 .I size
 511 under MIPS ECOFF.  Ignored for other object file formats.
 512
 513 .TP
 514 .B \-\-help
 515 Print a summary of the command-line options on the standard output and exit.
 516 This option and
 517 .B \-\-version
 518 begin with two dashes instead of one
 519 for compatibility with other GNU programs.  The other options start with
 520 only one dash for compatibility with other linkers.
 521
 522 .TP
 523 .B \-i
 524 Perform an incremental link (same as option \c
 525 .B \-r\c
 526 \&).
 527
 528 .TP
 529 .BI "\-l" "ar"\c
 530 \&
 531 Add an archive file \c
 532 .I ar\c
 533 \& to the list of files to link.  This
 534 option may be used any number of times.  \c
 535 .B ld\c
 536 \& will search its
 537 path-list for occurrences of \c
 538 .B lib\c
 539 .I ar\c
 540 \&.a\c
 541 \& for every \c
 542 .I ar
 543 specified.
 544
 545 .TP
 546 .BI "\-L" "searchdir"
 547 This command adds path \c
 548 .I searchdir\c
 549 \& to the list of paths that
 550 \c
 551 .B ld\c
 552 \& will search for archive libraries.  You may use this option
 553 any number of times.
 554
 555 The default set of paths searched (without being specified with
 556 \c
 557 .B \-L\c
 558 \&) depends on what emulation mode \c
 559 .B ld\c
 560 \& is using, and in
 561 some cases also on how it was configured.    The
 562 paths can also be specified in a link script with the \c
 563 .B SEARCH_DIR
 564 command.
 565
 566 .TP
 567 .B \-M
 568 Print (to the standard output file) a link map\(em\&diagnostic information
 569 about where symbols are mapped by \c
 570 .B ld\c
 571 \&, and information on global
 572 common storage allocation.
 573
 574 .TP
 575 .BI "\-Map " "mapfile"\c
 576 Print to the file
 577 .I mapfile
 578 a link map\(em\&diagnostic information
 579 about where symbols are mapped by \c
 580 .B ld\c
 581 \&, and information on global
 582 common storage allocation.
 583
 584 .TP
 585 .BI "\-m " "emulation"\c
 586 Emulate the
 587 .I emulation
 588 linker.  You can list the available emulations with the
 589 .I \-\-verbose
 590 or
 591 .I \-V
 592 options.  This option overrides the compiled-in default, which is the
 593 system for which you configured
 594 .BR ld .
 595
 596 .TP
 597 .B \-N
 598 specifies readable and writable \c
 599 .B text\c
 600 \& and \c
 601 .B data\c
 602 \& sections. If
 603 the output format supports Unix style magic numbers, the output is
 604 marked as \c
 605 .B OMAGIC\c
 606 \&.
 607
 608 When you use the `\|\c
 609 .B \-N\c
 610 \&\|' option, the linker does not page-align the
 611 data segment.
 612
 613 .TP
 614 .B \-n
 615 sets the text segment to be read only, and \c
 616 .B NMAGIC\c
 617 \& is written
 618 if possible.
 619
 620 .TP
 621 .B \-noinhibit\-exec
 622 Normally, the linker will not produce an output file if it encounters
 623 errors during the link process.  With this flag, you can specify that
 624 you wish the output file retained even after non-fatal errors.
 625
 626 .TP
 627 .B \-no\-keep\-memory
 628 The linker normally optimizes for speed over memory usage by caching
 629 the symbol tables of input files in memory.  This option tells the
 630 linker to instead optimize for memory usage, by rereading the symbol
 631 tables as necessary.  This may be required if the linker runs out of
 632 memory space while linking a large executable.
 633
 634 .TP
 635 .BI "\-o " "output"
 636 .I output\c
 637 \& is a name for the program produced by \c
 638 .B ld\c
 639 \&; if this
 640 option is not specified, the name `\|\c
 641 .B a.out\c
 642 \|' is used by default.  The
 643 script command \c
 644 .B OUTPUT\c
 645 \& can also specify the output file name.
 646
 647 .TP
 648 .BI "\-oformat " "output\-format"
 649 Specify the binary format for the output object file.
 650 You don't usually need to specify this, as
 651 \c
 652 .B ld\c
 653 \& is configured to produce as a default output format the most
 654 usual format on each machine.  \c
 655 .I output-format\c
 656 \& is a text string, the
 657 name of a particular format supported by the BFD libraries.
 658 The script command
 659 .B OUTPUT_FORMAT
 660 can also specify the output format, but this option overrides it.
 661
 662 .TP
 663 .BI "\-R " "filename"
 664 Read symbol names and their addresses from \c
 665 .I filename\c
 666 \&, but do not
 667 relocate it or include it in the output.  This allows your output file
 668 to refer symbolically to absolute locations of memory defined in other
 669 programs.
 670
 671 .TP
 672 .B \-relax
 673 An option with machine dependent effects.  Currently this option is only
 674 supported on the H8/300.
 675
 676 On some platforms, use this option to perform global optimizations that
 677 become possible when the linker resolves addressing in your program, such
 678 as relaxing address modes and synthesizing new instructions in the
 679 output object file.
 680
 681 On platforms where this is not supported, `\|\c
 682 .B \-relax\c
 683 \&\|' is accepted, but has no effect.
 684
 685 .TP
 686 .B \-r
 687 Generates relocatable output\(em\&i.e., generate an output file that can in
 688 turn serve as input to \c
 689 .B ld\c
 690 \&.  This is often called \c
 691 .I partial
 692 linking\c
 693 \&.  As a side effect, in environments that support standard Unix
 694 magic numbers, this option also sets the output file's magic number to
 695 \c
 696 .B OMAGIC\c
 697 \&.
 698 If this option is not specified, an absolute file is produced.  When
 699 linking C++ programs, this option \c
 700 .I will not\c
 701 \& resolve references to
 702 constructors; \c
 703 .B \-Ur\c
 704 \& is an alternative.
 705
 706 This option does the same as \c
 707 .B \-i\c
 708 \&.
 709
 710 .TP
 711 .B \-rpath\ \fIdirectory
 712 Add a directory to the runtime library search path.  This is used when
 713 linking an ELF executable with shared objects.  All
 714 .B \-rpath
 715 arguments are concatenated and passed to the runtime linker, which uses
 716 them to locate shared objects at runtime.  The
 717 .B \-rpath
 718 option is also used when locating shared objects which are needed by
 719 shared objects explicitly included in the link; see the description of
 720 the
 721 .B \-rpath\-link
 722 option.  If
 723 .B \-rpath
 724 is not used when linking an ELF executable, the contents of the
 725 environment variable
 726 .B LD_RUN_PATH
 727 will be used if it is defined.
 728
 729 The
 730 .B \-rpath
 731 option may also be used on SunOS.  By default, on SunOS, the linker
 732 will form a runtime search patch out of all the
 733 .B \-L
 734 options it is given.  If a
 735 .B \-rpath
 736 option is used, the runtime search path will be formed exclusively
 737 using the
 738 .B \-rpath
 739 options, ignoring
 740 the
 741 .B \-L
 742 options.  This can be useful when using gcc, which adds many
 743 .B \-L
 744 options which may be on NFS mounted filesystems.
 745
 746 .TP
 747 .B \-rpath\-link\ \fIdirectory
 748 When using ELF or SunOS, one shared library may require another.  This
 749 happens when an
 750 .B ld\ \-shared
 751 link includes a shared library as one of the input files.
 752
 753 When the linker encounters such a dependency when doing a non-shared,
 754 non-relocateable link, it will automatically try to locate the required
 755 shared library and include it in the link, if it is not included
 756 explicitly.  In such a case, the
 757 .B \-rpath\-link
 758 option specifies the first set of directories to search.  The
 759 .B \-rpath\-link
 760 option may specify a sequence of directory names either by specifying
 761 a list of names separated by colons, or by appearing multiple times.
 762
 763 If the required shared library is not found, the linker will issue a
 764 warning and continue with the link.
 765
 766 .TP
 767 .B \-S
 768 Omits debugger symbol information (but not all symbols) from the output file.
 769
 770 .TP
 771 .B \-s
 772 Omits all symbol information from the output file.
 773
 774 .TP
 775 .B \-shared
 776 Create a shared library.  This is currently only supported on ELF and
 777 SunOS platforms (on SunOS it is not required, as the linker will
 778 automatically create a shared library when there are undefined symbols
 779 and the
 780 .B \-e
 781 option is not used).
 782
 783 .TP
 784 .B \-sort\-common
 785 Normally, when
 786 .B ld
 787 places the global common symbols in the appropriate output sections,
 788 it sorts them by size.  First come all the one byte symbols, then all
 789 the two bytes, then all the four bytes, and then everything else.
 790 This is to prevent gaps between symbols due to
 791 alignment constraints.  This option disables that sorting.
 792
 793 .TP
 794 .B \-split\-by\-reloc\ \fIcount
 795 Trys to creates extra sections in the output file so that no single
 796 output section in the file contains more than
 797 .I count
 798 relocations.
 799 This is useful when generating huge relocatable for downloading into
 800 certain real time kernels with the COFF object file format; since COFF
 801 cannot represent more than 65535 relocations in a single section.
 802 Note that this will fail to work with object file formats which do not
 803 support arbitrary sections.  The linker will not split up individual
 804 input sections for redistribution, so if a single input section
 805 contains more than
 806 .I count
 807 relocations one output section will contain that many relocations.
 808
 809 .TP
 810 .B \-split\-by\-file
 811 Similar to
 812 .B \-split\-by\-reloc
 813 but creates a new output section for each input file.
 814
 815 .TP
 816 .BI "\-Tbss " "org"\c
 817 .TP
 818 .BI "\-Tdata " "org"\c
 819 .TP
 820 .BI "\-Ttext " "org"\c
 821 Use \c
 822 .I org\c
 823 \& as the starting address for\(em\&respectively\(em\&the
 824 \c
 825 .B bss\c
 826 \&, \c
 827 .B data\c
 828 \&, or the \c
 829 .B text\c
 830 \& segment of the output file.
 831 \c
 832 .I textorg\c
 833 \& must be a hexadecimal integer.
 834
 835 .TP
 836 .BI "\-T " "commandfile"
 837 Equivalent to \c
 838 .B \-c \c
 839 .I commandfile\c
 840 \&\c
 841 \&; supported for compatibility with
 842 other tools.
 843
 844 .TP
 845 .B \-t
 846 Prints names of input files as \c
 847 .B ld\c
 848 \& processes them.
 849
 850 .TP
 851 .BI "\-u " "sym"
 852 Forces \c
 853 .I sym\c
 854 \& to be entered in the output file as an undefined symbol.
 855 This may, for example, trigger linking of additional modules from
 856 standard libraries.  \c
 857 .B \-u\c
 858 \& may be repeated with different option
 859 arguments to enter additional undefined symbols.
 860
 861 .TP
 862 .B \-Ur
 863 For anything other than C++ programs, this option is equivalent to
 864 \c
 865 .B \-r\c
 866 \&: it generates relocatable output\(em\&i.e., an output file that can in
 867 turn serve as input to \c
 868 .B ld\c
 869 \&.  When linking C++ programs, \c
 870 .B \-Ur
 871 .I will\c
 872 \& resolve references to constructors, unlike \c
 873 .B \-r\c
 874 \&.
 875
 876 .TP
 877 .B \-\-verbose
 878 Display the version number for \c
 879 .B ld
 880 and list the supported emulations.
 881 Display which input files can and can not be opened.
 882
 883 .TP
 884 .B \-v, \-V
 885 Display the version number for \c
 886 .B ld\c
 887 \&.
 888 The
 889 .B \-V
 890 option also lists the supported emulations.
 891
 892 .TP
 893 .B \-\-version
 894 Display the version number for \c
 895 .B ld
 896 and exit.
 897
 898 .TP
 899 .B \-warn\-common
 900 Warn when a common symbol is combined with another common symbol or with
 901 a symbol definition.  Unix linkers allow this somewhat sloppy practice,
 902 but linkers on some other operating systems do not.  This option allows
 903 you to find potential problems from combining global symbols.
 904
 905 .TP
 906 .B \-warn\-constructors
 907 Warn if any global constructors are used.  This is only useful for a
 908 few object file formats.  For formats like COFF or ELF, the linker can
 909 not detect the use of global constructors.
 910
 911 .TP
 912 .B \-warn\-multiple\-gp
 913 Warn if the output file requires multiple global-pointer values.  This
 914 option is only meaningful for certain processors, such as the Alpha.
 915
 916 .TP
 917 .B \-warn\-once
 918 Only warn once for each undefined symbol, rather than once per module
 919 which refers to it.
 920
 921 .TP
 922 .B \-\-whole\-archive
 923 For each archive mentioned on the command line after the
 924 .B \-\-whole\-archive
 925 option, include every object file in the archive in the link, rather
 926 than searching the archive for the required object files.  This is
 927 normally used to turn an archive file into a shared library, forcing
 928 every object to be included in the resulting shared library.
 929
 930 .TP
 931 .B \-\-no\-whole\-archive
 932 Turn off the effect of the
 933 .B \-\-whole\-archive
 934 option for archives which appear later on the command line.
 935
 936 .TP
 937 .B \-X
 938 Delete all temporary local symbols.  For most targets, this is all local
 939 symbols whose names begin with `\|\c
 940 .B L\c
 941 \|'.
 942
 943 .TP
 944 .B \-x
 945 Delete all local symbols.
 946
 947 .PP
 948
 949 .SH ENVIRONMENT
 950 \c
 951 You can change the behavior of
 952 .B ld\c
 953 \& with the environment variable \c
 954 .B GNUTARGET\c
 955 \&.
 956
 957 \c
 958 .B GNUTARGET\c
 959 \& determines the input-file object format if you don't
 960 use \c
 961 .B \-b\c
 962 \& (or its synonym \c
 963 .B \-format\c
 964 \&).  Its value should be one
 965 of the BFD names for an input format.  If there is no
 966 \c
 967 .B GNUTARGET\c
 968 \& in the environment, \c
 969 .B ld\c
 970 \& uses the natural format
 971 of the host. If \c
 972 .B GNUTARGET\c
 973 \& is set to \c
 974 .B default\c
 975 \& then BFD attempts to discover the
 976 input format by examining binary input files; this method often
 977 succeeds, but there are potential ambiguities, since there is no method
 978 of ensuring that the magic number used to flag object-file formats is
 979 unique.  However, the configuration procedure for BFD on each system
 980 places the conventional format for that system first in the search-list,
 981 so ambiguities are resolved in favor of convention.
 982
 983 .PP
 984
 985 .SH "SEE ALSO"
 986
 987 .BR objdump ( 1 )
 988 .br
 989 .br
 990 .RB "`\|" ld "\|' and `\|" binutils "\|'"
 991 entries in
 992 .B info\c
 993 .br
 994 .I
 995 ld: the GNU linker\c
 996 , Steve Chamberlain and Roland Pesch;
 997 .I
 998 The GNU Binary Utilities\c
 999 , Roland H. Pesch.
1000
1001 .SH COPYING
1002 Copyright (c) 1991, 1992 Free Software Foundation, Inc.
1003 .PP
1004 Permission is granted to make and distribute verbatim copies of
1005 this manual provided the copyright notice and this permission notice
1006 are preserved on all copies.
1007 .PP
1008 Permission is granted to copy and distribute modified versions of this
1009 manual under the conditions for verbatim copying, provided that the
1010 entire resulting derived work is distributed under the terms of a
1011 permission notice identical to this one.
1012 .PP
1013 Permission is granted to copy and distribute translations of this
1014 manual into another language, under the above conditions for modified
1015 versions, except that this permission notice may be included in
1016 translations approved by the Free Software Foundation instead of in
1017 the original English.