externとは 意味・読み方・使い方

語源 1

From Middle French externe or its etymon Latin externus.

名詞

extern (plural externs)

1. A person affiliated with an institution in a lesser capacity, for example, as a non-resident or as a part-time affiliate.
   1. A day-scholar.
2. Outward form or part; exterior.

形容詞

extern

1. (obsolete, rare) External; outward; not inherent
   • c. 1603–1604 (date written), William Shakespeare, “The Tragedie of Othello, the Moore of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act I, scene i]:

     Heaven is my judge, not I for love and duty, / But seeming so, for my particular end, / For when my outward action doth demonstrate / The native act and figure of my heart / In complement extern, 'tis not long after / But I will wear my heart upon my sleeve / For daws to peck at.

   • 1663, Edward Waterhous[e], chapter XIV, in Fortescutus Illustratus; or A Commentary on that Nervous Treatise De Laudibus Legum Angliæ, Written by Sir John Fortescue Knight, […], London: […] Tho[mas] Roycroft for Thomas Dicas […], →OCLC, page 214:

     For if the ſoul of man vvere emancipated by virtue, it vvould not need any regulation or monition, beſides that of its invvard Tribunal; vvhich becauſe ſin does uſurp upon, has ſome relief from thoſe extern adjuments.

派生語

参照

• John A. Simpson and Edmund S. C. Weiner, editors (1989), “extern”, in The Oxford English Dictionary, 2nd edition, Oxford: Clarendon Press, →ISBN.
• William Shakespeare (1603) The Tragedy of Othello the Moor of Venice, Penguin Books, published 2001

語源 2

Short for external; used as a keyword in these programming languages.

名詞

extern (plural externs)

1. (programming) In the C and C++ programming languages, a variable that can be separately declared in many places, all of them referring to the same variable.
   • 1995, Martin L. Rinehart, Learn C++ Today!, page 552:

     Finally, get rid of the two function declarations and two externs that we added at the top of TEFIL.CPP so that we could support file_open().

   • 2018, Brian Beuken, The Fundamentals of C/C++ Game Programming:

     This is probably the big thing with C++, the more you can avoid global concepts and nasty externs the better, an object/class should be totally self-contained.