| This is gccgo.info, produced by makeinfo version 5.2 from gccgo.texi. |
| |
| Copyright (C) 2010-2015 Free Software Foundation, Inc. |
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| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with no |
| Invariant Sections, the Front-Cover Texts being (a) (see below), and |
| with the Back-Cover Texts being (b) (see below). A copy of the license |
| is included in the section entitled "GNU Free Documentation License". |
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| (a) The FSF's Front-Cover Text is: |
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| A GNU Manual |
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| (b) The FSF's Back-Cover Text is: |
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| You have freedom to copy and modify this GNU Manual, like GNU |
| software. Copies published by the Free Software Foundation raise funds |
| for GNU development. |
| INFO-DIR-SECTION Software development |
| START-INFO-DIR-ENTRY |
| * Gccgo: (gccgo). A GCC-based compiler for the Go language |
| END-INFO-DIR-ENTRY |
| |
| |
| Copyright (C) 2010-2015 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with no |
| Invariant Sections, the Front-Cover Texts being (a) (see below), and |
| with the Back-Cover Texts being (b) (see below). A copy of the license |
| is included in the section entitled "GNU Free Documentation License". |
| |
| (a) The FSF's Front-Cover Text is: |
| |
| A GNU Manual |
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| (b) The FSF's Back-Cover Text is: |
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| You have freedom to copy and modify this GNU Manual, like GNU |
| software. Copies published by the Free Software Foundation raise funds |
| for GNU development. |
| |
| |
| File: gccgo.info, Node: Top, Next: Copying, Up: (dir) |
| |
| Introduction |
| ************ |
| |
| This manual describes how to use 'gccgo', the GNU compiler for the Go |
| programming language. This manual is specifically about 'gccgo'. For |
| more information about the Go programming language in general, including |
| language specifications and standard package documentation, see |
| <http://golang.org/>. |
| |
| * Menu: |
| |
| * Copying:: The GNU General Public License. |
| * GNU Free Documentation License:: |
| How you can share and copy this manual. |
| * Invoking gccgo:: How to run gccgo. |
| * Import and Export:: Importing and exporting package data. |
| * C Interoperability:: Calling C from Go and vice-versa. |
| * Index:: Index. |
| |
| |
| File: gccgo.info, Node: Copying, Next: GNU Free Documentation License, Prev: Top, Up: Top |
| |
| GNU General Public License |
| ************************** |
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| Version 3, 29 June 2007 |
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| Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/> |
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| Preamble |
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| recipients of the covered work and works based on it. |
| |
| A patent license is "discriminatory" if it does not include within |
| the scope of its coverage, prohibits the exercise of, or is |
| conditioned on the non-exercise of one or more of the rights that |
| are specifically granted under this License. You may not convey a |
| covered work if you are a party to an arrangement with a third |
| party that is in the business of distributing software, under which |
| you make payment to the third party based on the extent of your |
| activity of conveying the work, and under which the third party |
| grants, to any of the parties who would receive the covered work |
| from you, a discriminatory patent license (a) in connection with |
| copies of the covered work conveyed by you (or copies made from |
| those copies), or (b) primarily for and in connection with specific |
| products or compilations that contain the covered work, unless you |
| entered into that arrangement, or that patent license was granted, |
| prior to 28 March 2007. |
| |
| Nothing in this License shall be construed as excluding or limiting |
| any implied license or other defenses to infringement that may |
| otherwise be available to you under applicable patent law. |
| |
| 12. No Surrender of Others' Freedom. |
| |
| If conditions are imposed on you (whether by court order, agreement |
| or otherwise) that contradict the conditions of this License, they |
| do not excuse you from the conditions of this License. If you |
| cannot convey a covered work so as to satisfy simultaneously your |
| obligations under this License and any other pertinent obligations, |
| then as a consequence you may not convey it at all. For example, |
| if you agree to terms that obligate you to collect a royalty for |
| further conveying from those to whom you convey the Program, the |
| only way you could satisfy both those terms and this License would |
| be to refrain entirely from conveying the Program. |
| |
| 13. Use with the GNU Affero General Public License. |
| |
| Notwithstanding any other provision of this License, you have |
| permission to link or combine any covered work with a work licensed |
| under version 3 of the GNU Affero General Public License into a |
| single combined work, and to convey the resulting work. The terms |
| of this License will continue to apply to the part which is the |
| covered work, but the special requirements of the GNU Affero |
| General Public License, section 13, concerning interaction through |
| a network will apply to the combination as such. |
| |
| 14. Revised Versions of this License. |
| |
| The Free Software Foundation may publish revised and/or new |
| versions of the GNU General Public License from time to time. Such |
| new versions will be similar in spirit to the present version, but |
| may differ in detail to address new problems or concerns. |
| |
| Each version is given a distinguishing version number. If the |
| Program specifies that a certain numbered version of the GNU |
| General Public License "or any later version" applies to it, you |
| have the option of following the terms and conditions either of |
| that numbered version or of any later version published by the Free |
| Software Foundation. If the Program does not specify a version |
| number of the GNU General Public License, you may choose any |
| version ever published by the Free Software Foundation. |
| |
| If the Program specifies that a proxy can decide which future |
| versions of the GNU General Public License can be used, that |
| proxy's public statement of acceptance of a version permanently |
| authorizes you to choose that version for the Program. |
| |
| Later license versions may give you additional or different |
| permissions. However, no additional obligations are imposed on any |
| author or copyright holder as a result of your choosing to follow a |
| later version. |
| |
| 15. Disclaimer of Warranty. |
| |
| THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY |
| APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE |
| COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" |
| WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, |
| INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE |
| RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. |
| SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL |
| NECESSARY SERVICING, REPAIR OR CORRECTION. |
| |
| 16. Limitation of Liability. |
| |
| IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN |
| WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES |
| AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR |
| DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR |
| CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE |
| THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA |
| BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD |
| PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER |
| PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF |
| THE POSSIBILITY OF SUCH DAMAGES. |
| |
| 17. Interpretation of Sections 15 and 16. |
| |
| If the disclaimer of warranty and limitation of liability provided |
| above cannot be given local legal effect according to their terms, |
| reviewing courts shall apply local law that most closely |
| approximates an absolute waiver of all civil liability in |
| connection with the Program, unless a warranty or assumption of |
| liability accompanies a copy of the Program in return for a fee. |
| |
| END OF TERMS AND CONDITIONS |
| =========================== |
| |
| How to Apply These Terms to Your New Programs |
| ============================================= |
| |
| If you develop a new program, and you want it to be of the greatest |
| possible use to the public, the best way to achieve this is to make it |
| free software which everyone can redistribute and change under these |
| terms. |
| |
| To do so, attach the following notices to the program. It is safest |
| to attach them to the start of each source file to most effectively |
| state the exclusion of warranty; and each file should have at least the |
| "copyright" line and a pointer to where the full notice is found. |
| |
| ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES. |
| Copyright (C) YEAR NAME OF AUTHOR |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation, either version 3 of the License, or (at |
| your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. |
| |
| Also add information on how to contact you by electronic and paper |
| mail. |
| |
| If the program does terminal interaction, make it output a short |
| notice like this when it starts in an interactive mode: |
| |
| PROGRAM Copyright (C) YEAR NAME OF AUTHOR |
| This program comes with ABSOLUTELY NO WARRANTY; for details type 'show w'. |
| This is free software, and you are welcome to redistribute it |
| under certain conditions; type 'show c' for details. |
| |
| The hypothetical commands 'show w' and 'show c' should show the |
| appropriate parts of the General Public License. Of course, your |
| program's commands might be different; for a GUI interface, you would |
| use an "about box". |
| |
| You should also get your employer (if you work as a programmer) or |
| school, if any, to sign a "copyright disclaimer" for the program, if |
| necessary. For more information on this, and how to apply and follow |
| the GNU GPL, see <http://www.gnu.org/licenses/>. |
| |
| The GNU General Public License does not permit incorporating your |
| program into proprietary programs. If your program is a subroutine |
| library, you may consider it more useful to permit linking proprietary |
| applications with the library. If this is what you want to do, use the |
| GNU Lesser General Public License instead of this License. But first, |
| please read <http://www.gnu.org/philosophy/why-not-lgpl.html>. |
| |
| |
| File: gccgo.info, Node: GNU Free Documentation License, Next: Invoking gccgo, Prev: Copying, Up: Top |
| |
| GNU Free Documentation License |
| ****************************** |
| |
| Version 1.3, 3 November 2008 |
| |
| Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc. |
| <http://fsf.org/> |
| |
| Everyone is permitted to copy and distribute verbatim copies |
| of this license document, but changing it is not allowed. |
| |
| 0. PREAMBLE |
| |
| The purpose of this License is to make a manual, textbook, or other |
| functional and useful document "free" in the sense of freedom: to |
| assure everyone the effective freedom to copy and redistribute it, |
| with or without modifying it, either commercially or |
| noncommercially. Secondarily, this License preserves for the |
| author and publisher a way to get credit for their work, while not |
| being considered responsible for modifications made by others. |
| |
| This License is a kind of "copyleft", which means that derivative |
| works of the document must themselves be free in the same sense. |
| It complements the GNU General Public License, which is a copyleft |
| license designed for free software. |
| |
| We have designed this License in order to use it for manuals for |
| free software, because free software needs free documentation: a |
| free program should come with manuals providing the same freedoms |
| that the software does. But this License is not limited to |
| software manuals; it can be used for any textual work, regardless |
| of subject matter or whether it is published as a printed book. We |
| recommend this License principally for works whose purpose is |
| instruction or reference. |
| |
| 1. APPLICABILITY AND DEFINITIONS |
| |
| This License applies to any manual or other work, in any medium, |
| that contains a notice placed by the copyright holder saying it can |
| be distributed under the terms of this License. Such a notice |
| grants a world-wide, royalty-free license, unlimited in duration, |
| to use that work under the conditions stated herein. The |
| "Document", below, refers to any such manual or work. Any member |
| of the public is a licensee, and is addressed as "you". You accept |
| the license if you copy, modify or distribute the work in a way |
| requiring permission under copyright law. |
| |
| A "Modified Version" of the Document means any work containing the |
| Document or a portion of it, either copied verbatim, or with |
| modifications and/or translated into another language. |
| |
| A "Secondary Section" is a named appendix or a front-matter section |
| of the Document that deals exclusively with the relationship of the |
| publishers or authors of the Document to the Document's overall |
| subject (or to related matters) and contains nothing that could |
| fall directly within that overall subject. (Thus, if the Document |
| is in part a textbook of mathematics, a Secondary Section may not |
| explain any mathematics.) The relationship could be a matter of |
| historical connection with the subject or with related matters, or |
| of legal, commercial, philosophical, ethical or political position |
| regarding them. |
| |
| The "Invariant Sections" are certain Secondary Sections whose |
| titles are designated, as being those of Invariant Sections, in the |
| notice that says that the Document is released under this License. |
| If a section does not fit the above definition of Secondary then it |
| is not allowed to be designated as Invariant. The Document may |
| contain zero Invariant Sections. If the Document does not identify |
| any Invariant Sections then there are none. |
| |
| The "Cover Texts" are certain short passages of text that are |
| listed, as Front-Cover Texts or Back-Cover Texts, in the notice |
| that says that the Document is released under this License. A |
| Front-Cover Text may be at most 5 words, and a Back-Cover Text may |
| be at most 25 words. |
| |
| A "Transparent" copy of the Document means a machine-readable copy, |
| represented in a format whose specification is available to the |
| general public, that is suitable for revising the document |
| straightforwardly with generic text editors or (for images composed |
| of pixels) generic paint programs or (for drawings) some widely |
| available drawing editor, and that is suitable for input to text |
| formatters or for automatic translation to a variety of formats |
| suitable for input to text formatters. A copy made in an otherwise |
| Transparent file format whose markup, or absence of markup, has |
| been arranged to thwart or discourage subsequent modification by |
| readers is not Transparent. An image format is not Transparent if |
| used for any substantial amount of text. A copy that is not |
| "Transparent" is called "Opaque". |
| |
| Examples of suitable formats for Transparent copies include plain |
| ASCII without markup, Texinfo input format, LaTeX input format, |
| SGML or XML using a publicly available DTD, and standard-conforming |
| simple HTML, PostScript or PDF designed for human modification. |
| Examples of transparent image formats include PNG, XCF and JPG. |
| Opaque formats include proprietary formats that can be read and |
| edited only by proprietary word processors, SGML or XML for which |
| the DTD and/or processing tools are not generally available, and |
| the machine-generated HTML, PostScript or PDF produced by some word |
| processors for output purposes only. |
| |
| The "Title Page" means, for a printed book, the title page itself, |
| plus such following pages as are needed to hold, legibly, the |
| material this License requires to appear in the title page. For |
| works in formats which do not have any title page as such, "Title |
| Page" means the text near the most prominent appearance of the |
| work's title, preceding the beginning of the body of the text. |
| |
| The "publisher" means any person or entity that distributes copies |
| of the Document to the public. |
| |
| A section "Entitled XYZ" means a named subunit of the Document |
| whose title either is precisely XYZ or contains XYZ in parentheses |
| following text that translates XYZ in another language. (Here XYZ |
| stands for a specific section name mentioned below, such as |
| "Acknowledgements", "Dedications", "Endorsements", or "History".) |
| To "Preserve the Title" of such a section when you modify the |
| Document means that it remains a section "Entitled XYZ" according |
| to this definition. |
| |
| The Document may include Warranty Disclaimers next to the notice |
| which states that this License applies to the Document. These |
| Warranty Disclaimers are considered to be included by reference in |
| this License, but only as regards disclaiming warranties: any other |
| implication that these Warranty Disclaimers may have is void and |
| has no effect on the meaning of this License. |
| |
| 2. VERBATIM COPYING |
| |
| You may copy and distribute the Document in any medium, either |
| commercially or noncommercially, provided that this License, the |
| copyright notices, and the license notice saying this License |
| applies to the Document are reproduced in all copies, and that you |
| add no other conditions whatsoever to those of this License. You |
| may not use technical measures to obstruct or control the reading |
| or further copying of the copies you make or distribute. However, |
| you may accept compensation in exchange for copies. If you |
| distribute a large enough number of copies you must also follow the |
| conditions in section 3. |
| |
| You may also lend copies, under the same conditions stated above, |
| and you may publicly display copies. |
| |
| 3. COPYING IN QUANTITY |
| |
| If you publish printed copies (or copies in media that commonly |
| have printed covers) of the Document, numbering more than 100, and |
| the Document's license notice requires Cover Texts, you must |
| enclose the copies in covers that carry, clearly and legibly, all |
| these Cover Texts: Front-Cover Texts on the front cover, and |
| Back-Cover Texts on the back cover. Both covers must also clearly |
| and legibly identify you as the publisher of these copies. The |
| front cover must present the full title with all words of the title |
| equally prominent and visible. You may add other material on the |
| covers in addition. Copying with changes limited to the covers, as |
| long as they preserve the title of the Document and satisfy these |
| conditions, can be treated as verbatim copying in other respects. |
| |
| If the required texts for either cover are too voluminous to fit |
| legibly, you should put the first ones listed (as many as fit |
| reasonably) on the actual cover, and continue the rest onto |
| adjacent pages. |
| |
| If you publish or distribute Opaque copies of the Document |
| numbering more than 100, you must either include a machine-readable |
| Transparent copy along with each Opaque copy, or state in or with |
| each Opaque copy a computer-network location from which the general |
| network-using public has access to download using public-standard |
| network protocols a complete Transparent copy of the Document, free |
| of added material. If you use the latter option, you must take |
| reasonably prudent steps, when you begin distribution of Opaque |
| copies in quantity, to ensure that this Transparent copy will |
| remain thus accessible at the stated location until at least one |
| year after the last time you distribute an Opaque copy (directly or |
| through your agents or retailers) of that edition to the public. |
| |
| It is requested, but not required, that you contact the authors of |
| the Document well before redistributing any large number of copies, |
| to give them a chance to provide you with an updated version of the |
| Document. |
| |
| 4. MODIFICATIONS |
| |
| You may copy and distribute a Modified Version of the Document |
| under the conditions of sections 2 and 3 above, provided that you |
| release the Modified Version under precisely this License, with the |
| Modified Version filling the role of the Document, thus licensing |
| distribution and modification of the Modified Version to whoever |
| possesses a copy of it. In addition, you must do these things in |
| the Modified Version: |
| |
| A. Use in the Title Page (and on the covers, if any) a title |
| distinct from that of the Document, and from those of previous |
| versions (which should, if there were any, be listed in the |
| History section of the Document). You may use the same title |
| as a previous version if the original publisher of that |
| version gives permission. |
| |
| B. List on the Title Page, as authors, one or more persons or |
| entities responsible for authorship of the modifications in |
| the Modified Version, together with at least five of the |
| principal authors of the Document (all of its principal |
| authors, if it has fewer than five), unless they release you |
| from this requirement. |
| |
| C. State on the Title page the name of the publisher of the |
| Modified Version, as the publisher. |
| |
| D. Preserve all the copyright notices of the Document. |
| |
| E. Add an appropriate copyright notice for your modifications |
| adjacent to the other copyright notices. |
| |
| F. Include, immediately after the copyright notices, a license |
| notice giving the public permission to use the Modified |
| Version under the terms of this License, in the form shown in |
| the Addendum below. |
| |
| G. Preserve in that license notice the full lists of Invariant |
| Sections and required Cover Texts given in the Document's |
| license notice. |
| |
| H. Include an unaltered copy of this License. |
| |
| I. Preserve the section Entitled "History", Preserve its Title, |
| and add to it an item stating at least the title, year, new |
| authors, and publisher of the Modified Version as given on the |
| Title Page. If there is no section Entitled "History" in the |
| Document, create one stating the title, year, authors, and |
| publisher of the Document as given on its Title Page, then add |
| an item describing the Modified Version as stated in the |
| previous sentence. |
| |
| J. Preserve the network location, if any, given in the Document |
| for public access to a Transparent copy of the Document, and |
| likewise the network locations given in the Document for |
| previous versions it was based on. These may be placed in the |
| "History" section. You may omit a network location for a work |
| that was published at least four years before the Document |
| itself, or if the original publisher of the version it refers |
| to gives permission. |
| |
| K. For any section Entitled "Acknowledgements" or "Dedications", |
| Preserve the Title of the section, and preserve in the section |
| all the substance and tone of each of the contributor |
| acknowledgements and/or dedications given therein. |
| |
| L. Preserve all the Invariant Sections of the Document, unaltered |
| in their text and in their titles. Section numbers or the |
| equivalent are not considered part of the section titles. |
| |
| M. Delete any section Entitled "Endorsements". Such a section |
| may not be included in the Modified Version. |
| |
| N. Do not retitle any existing section to be Entitled |
| "Endorsements" or to conflict in title with any Invariant |
| Section. |
| |
| O. Preserve any Warranty Disclaimers. |
| |
| If the Modified Version includes new front-matter sections or |
| appendices that qualify as Secondary Sections and contain no |
| material copied from the Document, you may at your option designate |
| some or all of these sections as invariant. To do this, add their |
| titles to the list of Invariant Sections in the Modified Version's |
| license notice. These titles must be distinct from any other |
| section titles. |
| |
| You may add a section Entitled "Endorsements", provided it contains |
| nothing but endorsements of your Modified Version by various |
| parties--for example, statements of peer review or that the text |
| has been approved by an organization as the authoritative |
| definition of a standard. |
| |
| You may add a passage of up to five words as a Front-Cover Text, |
| and a passage of up to 25 words as a Back-Cover Text, to the end of |
| the list of Cover Texts in the Modified Version. Only one passage |
| of Front-Cover Text and one of Back-Cover Text may be added by (or |
| through arrangements made by) any one entity. If the Document |
| already includes a cover text for the same cover, previously added |
| by you or by arrangement made by the same entity you are acting on |
| behalf of, you may not add another; but you may replace the old |
| one, on explicit permission from the previous publisher that added |
| the old one. |
| |
| The author(s) and publisher(s) of the Document do not by this |
| License give permission to use their names for publicity for or to |
| assert or imply endorsement of any Modified Version. |
| |
| 5. COMBINING DOCUMENTS |
| |
| You may combine the Document with other documents released under |
| this License, under the terms defined in section 4 above for |
| modified versions, provided that you include in the combination all |
| of the Invariant Sections of all of the original documents, |
| unmodified, and list them all as Invariant Sections of your |
| combined work in its license notice, and that you preserve all |
| their Warranty Disclaimers. |
| |
| The combined work need only contain one copy of this License, and |
| multiple identical Invariant Sections may be replaced with a single |
| copy. If there are multiple Invariant Sections with the same name |
| but different contents, make the title of each such section unique |
| by adding at the end of it, in parentheses, the name of the |
| original author or publisher of that section if known, or else a |
| unique number. Make the same adjustment to the section titles in |
| the list of Invariant Sections in the license notice of the |
| combined work. |
| |
| In the combination, you must combine any sections Entitled |
| "History" in the various original documents, forming one section |
| Entitled "History"; likewise combine any sections Entitled |
| "Acknowledgements", and any sections Entitled "Dedications". You |
| must delete all sections Entitled "Endorsements." |
| |
| 6. COLLECTIONS OF DOCUMENTS |
| |
| You may make a collection consisting of the Document and other |
| documents released under this License, and replace the individual |
| copies of this License in the various documents with a single copy |
| that is included in the collection, provided that you follow the |
| rules of this License for verbatim copying of each of the documents |
| in all other respects. |
| |
| You may extract a single document from such a collection, and |
| distribute it individually under this License, provided you insert |
| a copy of this License into the extracted document, and follow this |
| License in all other respects regarding verbatim copying of that |
| document. |
| |
| 7. AGGREGATION WITH INDEPENDENT WORKS |
| |
| A compilation of the Document or its derivatives with other |
| separate and independent documents or works, in or on a volume of a |
| storage or distribution medium, is called an "aggregate" if the |
| copyright resulting from the compilation is not used to limit the |
| legal rights of the compilation's users beyond what the individual |
| works permit. When the Document is included in an aggregate, this |
| License does not apply to the other works in the aggregate which |
| are not themselves derivative works of the Document. |
| |
| If the Cover Text requirement of section 3 is applicable to these |
| copies of the Document, then if the Document is less than one half |
| of the entire aggregate, the Document's Cover Texts may be placed |
| on covers that bracket the Document within the aggregate, or the |
| electronic equivalent of covers if the Document is in electronic |
| form. Otherwise they must appear on printed covers that bracket |
| the whole aggregate. |
| |
| 8. TRANSLATION |
| |
| Translation is considered a kind of modification, so you may |
| distribute translations of the Document under the terms of section |
| 4. Replacing Invariant Sections with translations requires special |
| permission from their copyright holders, but you may include |
| translations of some or all Invariant Sections in addition to the |
| original versions of these Invariant Sections. You may include a |
| translation of this License, and all the license notices in the |
| Document, and any Warranty Disclaimers, provided that you also |
| include the original English version of this License and the |
| original versions of those notices and disclaimers. In case of a |
| disagreement between the translation and the original version of |
| this License or a notice or disclaimer, the original version will |
| prevail. |
| |
| If a section in the Document is Entitled "Acknowledgements", |
| "Dedications", or "History", the requirement (section 4) to |
| Preserve its Title (section 1) will typically require changing the |
| actual title. |
| |
| 9. TERMINATION |
| |
| You may not copy, modify, sublicense, or distribute the Document |
| except as expressly provided under this License. Any attempt |
| otherwise to copy, modify, sublicense, or distribute it is void, |
| and will automatically terminate your rights under this License. |
| |
| However, if you cease all violation of this License, then your |
| license from a particular copyright holder is reinstated (a) |
| provisionally, unless and until the copyright holder explicitly and |
| finally terminates your license, and (b) permanently, if the |
| copyright holder fails to notify you of the violation by some |
| reasonable means prior to 60 days after the cessation. |
| |
| Moreover, your license from a particular copyright holder is |
| reinstated permanently if the copyright holder notifies you of the |
| violation by some reasonable means, this is the first time you have |
| received notice of violation of this License (for any work) from |
| that copyright holder, and you cure the violation prior to 30 days |
| after your receipt of the notice. |
| |
| Termination of your rights under this section does not terminate |
| the licenses of parties who have received copies or rights from you |
| under this License. If your rights have been terminated and not |
| permanently reinstated, receipt of a copy of some or all of the |
| same material does not give you any rights to use it. |
| |
| 10. FUTURE REVISIONS OF THIS LICENSE |
| |
| The Free Software Foundation may publish new, revised versions of |
| the GNU Free Documentation License from time to time. Such new |
| versions will be similar in spirit to the present version, but may |
| differ in detail to address new problems or concerns. See |
| <http://www.gnu.org/copyleft/>. |
| |
| Each version of the License is given a distinguishing version |
| number. If the Document specifies that a particular numbered |
| version of this License "or any later version" applies to it, you |
| have the option of following the terms and conditions either of |
| that specified version or of any later version that has been |
| published (not as a draft) by the Free Software Foundation. If the |
| Document does not specify a version number of this License, you may |
| choose any version ever published (not as a draft) by the Free |
| Software Foundation. If the Document specifies that a proxy can |
| decide which future versions of this License can be used, that |
| proxy's public statement of acceptance of a version permanently |
| authorizes you to choose that version for the Document. |
| |
| 11. RELICENSING |
| |
| "Massive Multiauthor Collaboration Site" (or "MMC Site") means any |
| World Wide Web server that publishes copyrightable works and also |
| provides prominent facilities for anybody to edit those works. A |
| public wiki that anybody can edit is an example of such a server. |
| A "Massive Multiauthor Collaboration" (or "MMC") contained in the |
| site means any set of copyrightable works thus published on the MMC |
| site. |
| |
| "CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0 |
| license published by Creative Commons Corporation, a not-for-profit |
| corporation with a principal place of business in San Francisco, |
| California, as well as future copyleft versions of that license |
| published by that same organization. |
| |
| "Incorporate" means to publish or republish a Document, in whole or |
| in part, as part of another Document. |
| |
| An MMC is "eligible for relicensing" if it is licensed under this |
| License, and if all works that were first published under this |
| License somewhere other than this MMC, and subsequently |
| incorporated in whole or in part into the MMC, (1) had no cover |
| texts or invariant sections, and (2) were thus incorporated prior |
| to November 1, 2008. |
| |
| The operator of an MMC Site may republish an MMC contained in the |
| site under CC-BY-SA on the same site at any time before August 1, |
| 2009, provided the MMC is eligible for relicensing. |
| |
| ADDENDUM: How to use this License for your documents |
| ==================================================== |
| |
| To use this License in a document you have written, include a copy of |
| the License in the document and put the following copyright and license |
| notices just after the title page: |
| |
| Copyright (C) YEAR YOUR NAME. |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 |
| or any later version published by the Free Software Foundation; |
| with no Invariant Sections, no Front-Cover Texts, and no Back-Cover |
| Texts. A copy of the license is included in the section entitled ``GNU |
| Free Documentation License''. |
| |
| If you have Invariant Sections, Front-Cover Texts and Back-Cover |
| Texts, replace the "with...Texts." line with this: |
| |
| with the Invariant Sections being LIST THEIR TITLES, with |
| the Front-Cover Texts being LIST, and with the Back-Cover Texts |
| being LIST. |
| |
| If you have Invariant Sections without Cover Texts, or some other |
| combination of the three, merge those two alternatives to suit the |
| situation. |
| |
| If your document contains nontrivial examples of program code, we |
| recommend releasing these examples in parallel under your choice of free |
| software license, such as the GNU General Public License, to permit |
| their use in free software. |
| |
| |
| File: gccgo.info, Node: Invoking gccgo, Next: Import and Export, Prev: GNU Free Documentation License, Up: Top |
| |
| 1 Invoking gccgo |
| **************** |
| |
| The 'gccgo' command is a frontend to 'gcc' and supports many of the same |
| options. *Note Option Summary: (gcc)Option Summary. This manual only |
| documents the options specific to 'gccgo'. |
| |
| The 'gccgo' command may be used to compile Go source code into an |
| object file, link a collection of object files together, or do both in |
| sequence. |
| |
| Go source code is compiled as packages. A package consists of one or |
| more Go source files. All the files in a single package must be |
| compiled together, by passing all the files as arguments to 'gccgo'. A |
| single invocation of 'gccgo' may only compile a single package. |
| |
| One Go package may 'import' a different Go package. The imported |
| package must have already been compiled; 'gccgo' will read the import |
| data directly from the compiled package. When this package is later |
| linked, the compiled form of the package must be included in the link |
| command. |
| |
| Go programs must generally be compiled with debugging information, |
| and '-g1' is the default as described below. Stripping a Go program |
| will generally cause it to misbehave or fail. |
| |
| '-IDIR' |
| Specify a directory to use when searching for an import package at |
| compile time. |
| |
| '-LDIR' |
| When linking, specify a library search directory, as with 'gcc'. |
| |
| '-fgo-pkgpath=STRING' |
| Set the package path to use. This sets the value returned by the |
| PkgPath method of reflect.Type objects. It is also used for the |
| names of globally visible symbols. The argument to this option |
| should normally be the string that will be used to import this |
| package after it has been installed; in other words, a pathname |
| within the directories specified by the '-I' option. |
| |
| '-fgo-prefix=STRING' |
| An alternative to '-fgo-pkgpath'. The argument will be combined |
| with the package name from the source file to produce the package |
| path. If '-fgo-pkgpath' is used, '-fgo-prefix' will be ignored. |
| |
| Go permits a single program to include more than one package with |
| the same name in the 'package' clause in the source file, though |
| obviously the two packages must be imported using different |
| pathnames. In order for this to work with 'gccgo', either |
| '-fgo-pkgpath' or '-fgo-prefix' must be specified when compiling a |
| package. |
| |
| Using either '-fgo-pkgpath' or '-fgo-prefix' disables the special |
| treatment of the 'main' package and permits that package to be |
| imported like any other. |
| |
| '-fgo-relative-import-path=DIR' |
| A relative import is an import that starts with './' or '../'. If |
| this option is used, 'gccgo' will use DIR as a prefix for the |
| relative import when searching for it. |
| |
| '-frequire-return-statement' |
| '-fno-require-return-statement' |
| By default 'gccgo' will warn about functions which have one or more |
| return parameters but lack an explicit 'return' statement. This |
| warning may be disabled using '-fno-require-return-statement'. |
| |
| '-fgo-check-divide-zero' |
| Add explicit checks for division by zero. In Go a division (or |
| modulos) by zero causes a panic. On Unix systems this is detected |
| in the runtime by catching the 'SIGFPE' signal. Some processors, |
| such as PowerPC, do not generate a SIGFPE on division by zero. |
| Some runtimes do not generate a signal that can be caught. On |
| those systems, this option may be used. Or the checks may be |
| removed via '-fno-go-check-divide-zero'. This option is currently |
| on by default, but in the future may be off by default on systems |
| that do not require it. |
| |
| '-fgo-check-divide-overflow' |
| Add explicit checks for division overflow. For example, division |
| overflow occurs when computing 'INT_MIN / -1'. In Go this should |
| be wrapped, to produce 'INT_MIN'. Some processors, such as x86, |
| generate a trap on division overflow. On those systems, this |
| option may be used. Or the checks may be removed via |
| '-fno-go-check-divide-overflow'. This option is currently on by |
| default, but in the future may be off by default on systems that do |
| not require it. |
| |
| '-g' |
| This is the standard 'gcc' option (*note Debugging Options: |
| (gcc)Debugging Options.). It is mentioned here because by default |
| 'gccgo' turns on debugging information generation with the |
| equivalent of the standard option '-g1'. This is because Go |
| programs require debugging information to be available in order to |
| get backtrace information. An explicit '-g0' may be used to |
| disable the generation of debugging information, in which case |
| certain standard library functions, such as 'runtime.Callers', will |
| not operate correctly. |
| |
| |
| File: gccgo.info, Node: Import and Export, Next: C Interoperability, Prev: Invoking gccgo, Up: Top |
| |
| 2 Import and Export |
| ******************* |
| |
| When 'gccgo' compiles a package which exports anything, the export |
| information will be stored directly in the object file. When a package |
| is imported, 'gccgo' must be able to find the file. |
| |
| When Go code imports the package 'GOPACKAGE', 'gccgo' will look for |
| the import data using the following filenames, using the first one that |
| it finds. |
| |
| 'GOPACKAGE.gox' |
| 'libGOPACKAGE.so' |
| 'libGOPACKAGE.a' |
| 'GOPACKAGE.o' |
| |
| The compiler will search for these files in the directories named by |
| any '-I' options, in order in which the directories appear on the |
| command line. The compiler will then search several standard system |
| directories. Finally the compiler will search the current directory (to |
| search the current directory earlier, use '-I.'). |
| |
| The compiler will extract the export information directly from the |
| compiled object file. The file 'GOPACKAGE.gox' will typically contain |
| nothing but export data. This can be generated from 'GOPACKAGE.o' via |
| |
| objcopy -j .go_export GOPACKAGE.o GOPACKAGE.gox |
| |
| For example, it may be desirable to extract the export information |
| from several different packages into their independent 'GOPACKAGE.gox' |
| files, and then to combine the different package object files together |
| into a single shared library or archive. |
| |
| At link time you must explicitly tell 'gccgo' which files to link |
| together into the executable, as is usual with 'gcc'. This is different |
| from the behaviour of other Go compilers. |
| |
| |
| File: gccgo.info, Node: C Interoperability, Next: Index, Prev: Import and Export, Up: Top |
| |
| 3 C Interoperability |
| ******************** |
| |
| When using 'gccgo' there is limited interoperability with C, or with C++ |
| code compiled using 'extern "C"'. |
| |
| This information is provided largely for documentation purposes. For |
| ordinary use it is best to build programs with the go tool and then use |
| 'import "C"', as described at <http://golang.org/cmd/cgo>. |
| |
| * Menu: |
| |
| * C Type Interoperability:: How C and Go types match up. |
| * Function Names:: How Go functions are named. |
| |
| |
| File: gccgo.info, Node: C Type Interoperability, Next: Function Names, Up: C Interoperability |
| |
| 3.1 C Type Interoperability |
| =========================== |
| |
| Basic types map directly: an 'int' in Go is an 'int' in C, etc. Go |
| 'byte' is equivalent to C 'unsigned char'. Pointers in Go are pointers |
| in C. A Go 'struct' is the same as C 'struct' with the same field names |
| and types. |
| |
| The Go 'string' type is currently defined as a two-element structure: |
| |
| struct __go_string { |
| const unsigned char *__data; |
| int __length; |
| }; |
| |
| You can't pass arrays between C and Go. However, a pointer to an |
| array in Go is equivalent to a C pointer to the equivalent of the |
| element type. For example, Go '*[10]int' is equivalent to C 'int*', |
| assuming that the C pointer does point to 10 elements. |
| |
| A slice in Go is a structure. The current definition is: |
| |
| struct __go_slice { |
| void *__values; |
| int __count; |
| int __capacity; |
| }; |
| |
| The type of a Go function with no receiver is equivalent to a C |
| function whose parameter types are equivalent. When a Go function |
| returns more than one value, the C function returns a struct. For |
| example, these functions have equivalent types: |
| |
| func GoFunction(int) (int, float) |
| struct { int i; float f; } CFunction(int) |
| |
| A pointer to a Go function is equivalent to a pointer to a C function |
| when the functions have equivalent types. |
| |
| Go 'interface', 'channel', and 'map' types have no corresponding C |
| type ('interface' is a two-element struct and 'channel' and 'map' are |
| pointers to structs in C, but the structs are deliberately |
| undocumented). C 'enum' types correspond to some integer type, but |
| precisely which one is difficult to predict in general; use a cast. C |
| 'union' types have no corresponding Go type. C 'struct' types |
| containing bitfields have no corresponding Go type. C++ 'class' types |
| have no corresponding Go type. |
| |
| Memory allocation is completely different between C and Go, as Go |
| uses garbage collection. The exact guidelines in this area are |
| undetermined, but it is likely that it will be permitted to pass a |
| pointer to allocated memory from C to Go. The responsibility of |
| eventually freeing the pointer will remain with C side, and of course if |
| the C side frees the pointer while the Go side still has a copy the |
| program will fail. When passing a pointer from Go to C, the Go function |
| must retain a visible copy of it in some Go variable. Otherwise the Go |
| garbage collector may delete the pointer while the C function is still |
| using it. |
| |
| |
| File: gccgo.info, Node: Function Names, Prev: C Type Interoperability, Up: C Interoperability |
| |
| 3.2 Function Names |
| ================== |
| |
| Go code can call C functions directly using a Go extension implemented |
| in 'gccgo': a function declaration may be preceded by a comment giving |
| the external name. The comment must be at the beginning of the line and |
| must start with '//extern'. This must be followed by a space and then |
| the external name of the function. The function declaration must be on |
| the line immediately after the comment. For example, here is how the C |
| function 'open' can be declared in Go: |
| |
| //extern open |
| func c_open(name *byte, mode int, perm int) int |
| |
| The C function naturally expects a nul terminated string, which in Go |
| is equivalent to a pointer to an array (not a slice!) of 'byte' with a |
| terminating zero byte. So a sample call from Go would look like (after |
| importing the 'os' package): |
| |
| var name = [4]byte{'f', 'o', 'o', 0}; |
| i := c_open(&name[0], os.O_RDONLY, 0); |
| |
| Note that this serves as an example only. To open a file in Go |
| please use Go's 'os.Open' function instead. |
| |
| The name of Go functions accessed from C is subject to change. At |
| present the name of a Go function that does not have a receiver is |
| 'prefix.package.Functionname'. The prefix is set by the '-fgo-prefix' |
| option used when the package is compiled; if the option is not used, the |
| default is simply 'go'. To call the function from C you must set the |
| name using the 'gcc' '__asm__' extension. |
| |
| extern int go_function(int) __asm__ ("myprefix.mypackage.Function"); |
| |
| |
| File: gccgo.info, Node: Index, Prev: C Interoperability, Up: Top |
| |
| Index |
| ***** |
| |
| [index] |
| * Menu: |
| |
| * '-fgo-check-divide-overflow': Invoking gccgo. (line 83) |
| * '-fgo-check-divide-zero': Invoking gccgo. (line 72) |
| * '-fgo-pkgpath': Invoking gccgo. (line 37) |
| * '-fgo-prefix': Invoking gccgo. (line 45) |
| * '-fgo-relative-import-path': Invoking gccgo. (line 61) |
| * '-fno-go-check-divide-overflow': Invoking gccgo. (line 83) |
| * '-fno-go-check-divide-zero': Invoking gccgo. (line 72) |
| * '-fno-require-return-statement': Invoking gccgo. (line 67) |
| * '-frequire-return-statement': Invoking gccgo. (line 67) |
| * '-g for gccgo': Invoking gccgo. (line 93) |
| * '-I': Invoking gccgo. (line 30) |
| * '-L': Invoking gccgo. (line 34) |
| * '.gox': Import and Export. (line 10) |
| * 'extern': Function Names. (line 6) |
| * external names: Function Names. (line 6) |
| * FDL, GNU Free Documentation License: GNU Free Documentation License. |
| (line 6) |
| * 'slice' in C: C Type Interoperability. |
| (line 23) |
| * 'string' in C: C Type Interoperability. |
| (line 11) |
| |
| |
| |
| Tag Table: |
| Node: Top1688 |
| Node: Copying2482 |
| Node: GNU Free Documentation License40016 |
| Node: Invoking gccgo65144 |
| Node: Import and Export69966 |
| Node: C Interoperability71562 |
| Node: C Type Interoperability72146 |
| Node: Function Names74705 |
| Node: Index76307 |
| |
| End Tag Table |