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标题: 函数大全(e开头) [打印本页]

作者: 韩冰 时间: 2004-10-4 03:01
标题: 函数大全(e开头)
<

align=center>函数大全(e开头)


<

>函数名: ecvt 
功能: 把一个浮点数转换为字符串
用法: char ecvt(double value, int ndigit, int *decpt, int *sign);
程序例: 
<

>#include <STDLIB.H>
#include <STDIO.H>
#include <CONIO.H>
<

>int main(void)
{
char *string;
double value;
int dec, sign;
int ndig = 10; 
<

>clrscr();
value = 9.876;
string = ecvt(value, ndig, &dec, &sign);
printf("string = %s dec = %d \
sign = %d\n", string, dec, sign); 
<

>value = -123.45;
ndig= 15;
string = ecvt(value,ndig,&dec,&sign);
printf("string = %s dec = %d sign = %d\n",
string, dec, sign);

<

>value = 0.6789e5; /* scientific
notation */
ndig = 5;
string = ecvt(value,ndig,&dec,&sign);
printf("string = %s dec = %d\
sign = %d\n", string, dec, sign); 
<

>return 0;
} 


<

>函数名: ellipse 
功能: 画一椭圆
用法: void far ellipse(int x, int y, int stangle, int endangle,
int xradius, int yradius);
程序例: 
<

>#include <GRAPHICS.H>
#include <STDLIB.H>
#include <STDIO.H>
#include <CONIO.H>
<

>int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int midx, midy;
int stangle = 0, endangle = 360;
int xradius = 100, yradius = 50; 
<

>/* initialize graphics, local variables */
initgraph(&gdriver, &gmode, ""); 
<

>/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk)
/* an error occurred */
{
printf("Graphics error: %s\n",
grapherrormsg(errorcode));
printf("

ress any key to halt:");
getch();
exit(1);
/* terminate with an error code */
} 
<

>midx = getmaxx() / 2;
midy = getmaxy() / 2;
setcolor(getmaxcolor()); 
<

>/* draw ellipse */
ellipse(midx, midy, stangle, endangle,
xradius, yradius); 
<

>/* clean up */
getch();
closegraph();
return 0;
} 


<

>函数名: enable 
功能: 开放硬件中断
用法: void enable(void);
程序例: 
<

>/* ** NOTE:
This is an interrupt service routine. You can NOT compile this program
with Test Stack Overflow turned on and get an executable file which will
operate correctly.
*/ 
<

>#include <STDIO.H>
#include <DOS.H>
#include <CONIO.H>
<

>/* The clock tick interrupt */
#define INTR 0X1C 
<

>void interrupt ( *oldhandler)(void); 
<

>int count=0; 
<

>void interrupt handler(void)
{
/*
disable interrupts during the handling of the interrupt
*/
disable();
/* increase the global counter */
count++;
/*
re enable interrupts at the end of the handler
*/
enable();
/* call the old routine */
oldhandler();
} 
<

>int main(void)
{
/* save the old interrupt vector */
oldhandler = getvect(INTR); 
<

>/* install the new interrupt handler */
setvect(INTR, handler); 
<

>/* loop until the counter exceeds 20 */
while (count < 20)
printf("count is %d\n",count); 
<

>/* reset the old interrupt handler */
setvect(INTR, oldhandler); 
<

>return 0;
} 


<

>函数名: eof 
功能: 检测文件结束
用法: int eof(int *handle);
程序例: 
#include <SYS\STAT.H>
#include <STRING.H>
#include <STDIO.H>
#include <FCNTL.H>
#include <IO.H>
int main(void)
{
int handle;
char msg[] = "This is a test";
char ch; 
/* create a file */
handle = open("DUMMY.FIL",
O_CREAT | O_RDWR,
S_IREAD | S_IWRITE); 
/* write some data to the file */
write(handle, msg, strlen(msg)); 
/* seek to the beginning of the file */
lseek(handle, 0L, SEEK_SET); 
/*
reads chars from the file until hit EOF
*/
do
{
read(handle, &ch, 1);
printf("%c", ch);
} while (!eof(handle)); 
close(handle);
return 0;
}


函数名: exec... 
功能: 装入并运行其它程序的函数
用法: int execl(char *pathname, char *arg0, arg1, ..., argn, NULL);
int execle(char *pathname, char *arg0, arg1, ..., argn, NULL,
char *envp[]);
int execlp(char *pathname, char *arg0, arg1, .., NULL);
int execple(char *pathname, char *arg0, arg1, ..., NULL,
char *envp[]);
int execv(char *pathname, char *argv[]);
int execve(char *pathname, char *argv[], char *envp[]);
int execvp(char *pathname, char *argv[]);
int execvpe(char *pathname, char *argv[], char *envp[]);
程序例: 
/* execv example */
#include <PROCESS.H>
#include <STDIO.H>
#include <ERRNO.H>
void main(int argc, char *argv[])
{
int i; 
printf("Command line arguments:\n");
for (i=0; i<ARGC; printf("[%2d] : %s\n", i, argv); 
& r1 {+ `; \6 ?4 g6 F" Pprintf("About to exec child with arg1 arg2 ...\n");
9 y _! X) t% |6 s6 Mexecv("CHILD.EXE", argv); 5 ?4 ^4 K5 t r/ u' K
perror("exec error"); 
/ z$ N- f& [# ^( X9 ]exit(1);
- @' A1 N: K1 o. v3 [" R( R& ?}
 f' b: ?: B# ~( U/ h3 z& F3 L( [4 }+ C4 d) ^, P0 B. W( H
* n2 T# ]" D; {0 T6 @
函数名: exit 
7 a+ c+ B9 o5 D* ~! W) o功能: 终止程序 9 b- a- u& D1 j2 o) m7 ?1 H
用法: void exit(int status);
; S9 c' X+ m7 ~+ U0 r6 G- I" x5 Z+ C9 Z程序例: . t+ J+ f4 A+ h' O3 A% {& n H
#include <STDLIB.H>/ W8 g' B+ i* N4 j' X% F+ W$ C
#include <CONIO.H>1 U! f$ O. r& f: A. B8 u
#include <STDIO.H>' \' W- I# L. [
int main(void) # Y3 | U% [! h" r c1 q/ T4 g
{
6 |3 c6 j5 h9 a7 T; r! b( zint status; 
2 ?$ f7 o& X. Vprintf("Enter either 1 or 2\n"); 7 u" |5 d) S+ X5 R% u; D# r
status = getch(); & ?0 e% a% N) H1 S5 I
/* Sets DOS errorlevel */ - E7 z3 Y" V- E2 P1 s
exit(status - '0'); 
9 G4 t8 V0 i/ E" I- e. |! {/* Note: this line is never reached */ 2 \) J' y7 H+ O2 ^) U |7 X/ V
return 0; ' l( K, I! Y/ w0 ?$ ?1 ?+ L
} , m. j' v1 D/ @% P3 W
- p/ g. i* p) P) v3 I9 A

6 y1 a# f' ?% Y/ W6 g: K/ U函数名: exp " u' `- X6 r+ K$ o D, m
功能: 指数函数 / m3 a2 g# L6 O* A. R9 ]$ k
用法: double exp(double x); + O( \" w* W+ u; x
程序例: 
: _" ?2 c& j+ Q+ N9 J' h#include <STDIO.H>& s; T+ I8 c/ a
#include <MATH.H>% x+ u- D$ d) ?
int main(void) / I& d8 U7 o7 |0 U
{ * j+ O- Z* t! ^0 L3 m5 D3 N; O' J
double result; ! K/ ]2 @. C; I/ ~7 [" {) e
double x = 4.0; 
) X+ r( W1 h A' Oresult = exp(x);
* l( _, S" ?& ]+ R6 y Qprintf("'e' raised to the power \ 6 s' e8 f$ |: }; |8 k
of %lf (e ^ %lf) = %lf\n",
- l' r2 i4 i4 T* w9 q( u1 \' Bx, x, result); 4 Y# z _4 b: k9 F6 t
return 0;
) ?6 x# y/ @2 F. g$ ^2 k& f( c}
% r5 G1 S- i* b2 }! Z& b# m
作者: 韩冰 时间: 2004-10-4 03:02
< align=center>函数大全(d开头)+ ~ d# |0 I4 H% B. Q5 Q; _
" b2 H4 q: z; s+ M$ a8 D
<>函数名: delay 
. Y' U# T6 E X0 Y! g功能: 将程序的执行暂停一段时间(毫秒) & V0 w* B. Y. K/ M( _8 n
用法: void delay(unsigned milliseconds);
& B' ?0 G: |9 ^' |! e1 ]程序例: 0 w( G9 D' ` }! ?
/* Emits a 440-Hz tone for 500 milliseconds */
, r. Z m" y+ n" G. ^/ F$ [#include <DOS.H><>int main(void) 6 ^9 O6 Z# V4 U5 S- y: G
{
* X9 o! [- w/ b; K gsound(440); . k8 ~3 @ K; q) Y" }, S
delay(500); * R' A. C- y1 I! c
nosound(); <>return 0;
: t( i9 o X+ L6 n5 U2 L} 5 B, P* \' Y" v( i
+ e' z, D7 t7 m. f( d; j
<>函数名: delline & J K6 j% Q: I
功能: 在文本窗口中删去一行
1 Q1 N$ R/ Y7 Y( X- u用法: void delline(void); # _0 B- O* K# f& E, r: q) K
程序例: <>#include <CONIO.H><>int main(void) ) M& m, o8 [& ?2 d8 H
{
/ y: x# n' t# W4 N+ u* ]7 Dclrscr(); 1 \3 J& A0 n0 D
cprintf("The function DELLINE deletes \ 8 E: k3 _" }. f1 P: `3 v! l3 V4 r; T
the line containing the\r\n"); . o }, b: F8 ~, \. o
cprintf("cursor and moves all lines \ ; c% _; J! M, R `' _8 x
below it one line up.\r\n");
5 p8 f, u% Z& q. Q' ?1 [cprintf("DELLINE operates within the \ ) V: @, N& N E
currently active text\r\n"); & g4 C' b) y" B% Y6 g
cprintf("window. Press any key to \ 5 g# Z0 t; b. }0 a9 v# S
continue . . .");
* l: Q2 O* ?6 h; Jgotoxy(1,2); /* Move the cursor to the
 x/ Y( F" x5 P6 S+ g2 f3 Gsecond line and first column */
9 q) m; m& p/ r! H6 S: j6 Xgetch(); <>delline(); , p9 v( s6 w9 |' e, h
getch(); <>return 0;
: x0 }0 k. |8 C8 U% k' y) W- I} % q/ H" Q. ~* z& K a* ^& \
<>函数名: detectgraph & Z2 P7 L" { h' L) j$ t! X
功能: 通过检测硬件确定图形驱动程序和模式 + c1 a# N" }& @7 I- C L* z) L6 s. t
用法: void far detectgraph(int far *graphdriver, int far *graphmode);
# n) p3 Q; n, b h: r9 Y4 ~# b程序例: <>#include <GRAPHICS.H>1 @$ x5 x& F) N. x
#include <STDLIB.H>
# V2 ?1 w' z, S/ t2 q#include <STDIO.H>% `& Y0 o+ w9 L# g3 o6 ?: l
#include <CONIO.H><>/* names of the various cards supported */ 5 e: U9 B' ~& F2 k3 P( V
char *dname[] = { "requests detection", 9 c# Q* f! I8 p: U* |
"a CGA",
1 F, ~( z3 g' F( c"an MCGA",
" A2 \. W! L! R, r. H+ ^"an EGA",
6 g/ }8 C4 `0 q4 w5 u- Y* P"a 64K EGA",
7 _. b7 o/ B% k5 F& l"a monochrome EGA", + u# C7 L4 c% j* R7 {1 Y* |
"an IBM 8514",
1 u0 L$ I) G8 v6 |& ?2 g& ?5 n+ v"a Hercules monochrome",
2 E& J# I" z+ G$ e4 j) R6 y+ }: v"an AT&T 6300 PC",
9 v2 q! u, x1 g6 O& ^"a VGA",
* [/ b I$ Y9 o* H$ N5 q7 t"an IBM 3270 PC" ! V! ]* B9 x* P0 i
}; <>int main(void)
 C @) _& t( M; l7 _, f2 r. B{
6 h6 k- S4 b0 B- c ?/* returns detected hardware info. */ 0 t) _. B3 t+ P8 P* O9 [
int gdriver, gmode, errorcode; <>/* detect graphics hardware available */
$ F! u- @9 S: ^0 ndetectgraph(&gdriver, &gmode); <>/* read result of detectgraph call */ 6 y# f) W6 @4 E: U+ v# g
errorcode = graphresult();
4 x( v: g/ {9 W3 f' X9 |if (errorcode != grOk) /* an error 9 B( }7 s! a6 V1 V: \, P, H( u: U
occurred */ . x; [8 Y6 Q) t. k: n8 i! x& ?
{
5 s4 a! f5 ?7 {* Uprintf("Graphics error: %s\n", \ " \' i) _0 A* e
grapherrormsg(errorcode));
% M# v3 I. n" I! P/ Aprintf("ress any key to halt:");
) F7 V r, J/ }3 Lgetch(); * y9 ?2 G/ p& Y' R) U; J% b1 S
exit(1); /* terminate with an error
9 c \5 t8 q4 {% F1 icode */ " P' d/ W& W$ R9 g+ F) `
} <>/* display the information detected */
3 \) _( A8 a3 l0 I D; j- ~clrscr();
- b# C1 ?: K! }; pprintf("You have %s video display \ 2 O; W9 z# e1 ~% r
card.\n", dname[gdriver]); 5 h2 E! t( D) D' K
printf("ress any key to halt:"); 0 B! r; c( e, c2 c3 M4 Y6 v
getch(); 0 O2 ^5 \( z0 O
return 0;
8 t4 ], g C3 G; S} 
$ r8 @# f0 ^5 v1 t+ f! V4 `/ v( x7 `; c0 x) @" f

; f( C1 s) N& R0 C6 M/ C<>函数名: difftime " \& g3 l& }" ] u0 A7 ]
功能: 计算两个时刻之间的时间差
: K! T& }4 k2 [2 Q8 ^' {: t用法: double difftime(time_t time2, time_t time1);
- {' l0 d& s B程序例: <>#include <TIME.H>
# H7 j3 P* `# Z. c2 a2 u# V' X4 f#include <STDIO.H>
- O) @8 k- q, L3 J2 Z#include <DOS.H>
5 |# U |0 n5 R1 Z/ y, w! Q#include <CONIO.H><>int main(void) 6 f" o4 W4 i/ D
{ - z, v& N& s- b# U, Y+ A) ]
time_t first, second; <>clrscr(); ' e6 n, I" j$ X, D4 Z4 M) H4 @4 W
first = time(NULL); /* Gets system
+ l7 E; U' G6 \ atime */ 4 d) ~' @+ l2 \% {0 X
delay(2000); /* Waits 2 secs */
 q) Q; B7 z- C5 |second = time(NULL); /* Gets system time ! w# w2 L+ ^( j8 Z; _
again */ <>printf("The difference is: %f \ $ O, c: j7 H( x
seconds\n",difftime(second,first));
4 e; N- [/ I/ m; w! }5 B( A- ^getch(); <>return 0; S. Z; _) }' f1 I/ ]" i) R: x
} ( x& Y/ M0 a5 D: r! y4 A; r Y
! O8 f b F: W' Y4 i4 U2 ]
<>函数名: disable 
8 p, }7 Z7 E- W7 t, `( W功能: 屏蔽中断 ) d9 Y0 t$ Y$ W+ F
用法: void disable(void); / ~9 [/ Q0 ]. U# S
程序例: <>/***NOTE: This is an interrupt service
- g, ~$ X# s) W2 A# T" L# Z+ ~routine. You cannot compile this program
& Y) y( z4 c% r- p6 Jwith Test Stack Overflow turned on and 4 c4 `7 x: o+ i8 b2 b
get an executable file that operates
3 D) v/ M2 B d5 Y8 d6 Xcorrectly. */ <>#include <STDIO.H>
9 s6 {: O6 k4 G4 I1 g4 P+ `% w# P#include <DOS.H>
5 ]0 i& H# J) |/ x#include <CONIO.H><>#define INTR 0X1C /* The clock tick 1 [4 W4 H7 b+ f: t5 e
interrupt */ <>void interrupt ( *oldhandler)(void); <>int count=0; void interrupt handler(void)
: R6 O# C# A* S, ^6 l+ o{
( R1 |( n% V4 | b/* disable interrupts during the handling of / ^" U- p4 m; ?5 W( B8 P% E' [
the interrupt */
- e8 Z/ ^7 C& o# U6 udisable(); 8 J w9 E2 n' g# h; N3 q( W
/* increase the global counter */ ! w& U- Z7 @) d' T. O# J9 `2 f7 I
count++; 3 g0 y+ e$ L0 {1 R( v
/* reenable interrupts at the end of the ! M1 x0 ?) x, }7 y/ r
handler */ / \% i0 S2 n& V5 k/ G! p1 i# e
enable();
3 w! _+ i/ Z8 S7 l( d8 j+ D2 A/* call the old routine */ ' [$ g7 c6 o$ ^ C2 r {6 v
oldhandler(); * Y! q) f- V) R
} int main(void)
/ V0 i9 {" Y2 l! M& @- Q{
( [0 o: S9 k4 T, _' ^" {2 ~' m/* save the old interrupt vector */
/ j7 J* a# g( _* m5 h" Ioldhandler = getvect(INTR); /* install the new interrupt handler */
# k8 T' c9 E* X0 [setvect(INTR, handler); /* loop until the counter exceeds 20 */ & Y' n- F. P6 j. D) n" _4 K/ p, m7 h
while (count < 20)
$ Q! Z8 ^4 M& qprintf("count is %d\n",count); /* reset the old interrupt handler */
* w. s; @7 G) csetvect(INTR, oldhandler); return 0;
0 t b7 I0 A" X} 函数名: div " x( ^; b. t1 }* `
功能: 将两个整数相除, 返回商和余数
5 K+ N+ S7 T) x1 q- \* Q4 E用法: div_t (int number, int denom); ) r- u, i. h0 b7 X7 T7 q
程序例: #include <STDLIB.H>
& r2 x4 ?; Q, S#include <STDIO.H>div_t x; int main(void)
# j( ^$ I1 V4 d7 J, t( y{ " U" Y, j' _+ R! b+ b! g
x = div(10,3);
% D9 S3 ~0 O/ V1 \' O6 v$ `' [printf("10 div 3 = %d remainder %d\n", x.quot, x.rem); return 0;
1 b/ I3 Y& w2 X2 W( w H1 ]} % q$ g$ o& p2 p3 Z$ C

2 F1 A& F0 ?3 m" j1 s函数名: dosexterr 
8 Y2 ^$ ?4 [# @5 k7 C) b# s2 Q功能: 获取扩展DOS错误信息
6 H9 c4 y$ O1 M+ O% |用法: int dosexterr(struct DOSERR *dblkp);
$ U- ]7 @3 }; y- N2 \程序例: #include <STDIO.H>6 x8 z2 F- H6 m; x; r: O8 r+ C
#include <DOS.H>int main(void) ; f6 ]0 E' f% d( m7 z: i& R5 G
{
: d- f8 ^4 _2 t4 f, JFILE *fp;
, V. @+ E) C" j" Dstruct DOSERROR info; fp = fopen("perror.dat","r"); ) G$ D. {; ?. O' Q+ U
if (!fp) perror("Unable to open file for
/ i' ]; `! r6 E! j0 M y' z8 kreading");
& f8 R2 T9 B3 r+ U9 y: gdosexterr(&info); printf("Extended DOS error \
! y8 H3 E& g( |* T7 [information:\n");
0 ], x! Q& A9 l* x {" |printf(" Extended error: \
/ F3 @2 ]% x, d! |3 @) }. S. b, x%d\n",info.exterror); 8 u p/ J. }% N- r
printf(" Class: \
4 l# {; t1 p* B9 m%x\n",info.class);
( _8 Y. O N) f; B1 Iprintf(" Action: \ H5 W+ W6 Q. o4 i
%x\n",info.action); 8 O1 p5 k/ H/ K2 j
printf(" Error Locus: \ : Z& q; i0 y9 A) s! O( K* c
%x\n",info.locus); return 0; 3 W2 w7 Y' S- [6 T( ^# }
} 
, H! g& L0 T& @( R( t+ E
0 r( }2 y7 u* T3 ]% r. m函数名: dostounix 
9 y. J! E/ x% n; [功能: 转换日期和时间为UNIX时间格式
( n( Z/ P7 J2 x; T) R& I用法: long dostounix(struct date *dateptr, struct time *timeptr); " T, ?8 Z! O# g' }
程序例: #include <TIME.H>
+ P7 f# H- V& s$ j/ g#include <STDDEF.H>
% U& l0 ?) y" H5 G#include <DOS.H>
8 K- S( y* O) U9 f% |, X#include <STDIO.H>int main(void) " ]4 B% d) n8 k- g; p# q, x& j' b x
{ 7 Q5 m/ {- v) j% |( @
time_t t;
, H0 F6 ] ?" s* Hstruct time d_time;
* _+ B; z" i0 C1 v' R, P, D2 P+ estruct date d_date; 3 y ^* V$ n# V2 {% ~2 H
struct tm *local; getdate(&d_date);
8 p$ H- W7 a0 Q2 g5 _6 Ugettime(&d_time); t = dostounix(&d_date, &d_time); ' C3 W. x+ U" i& N5 S/ Q2 q
local = localtime(&t);
0 v3 i4 `5 \" Kprintf("Time and Date: %s\n", \
$ C/ X$ @, T. c+ C/ G6 Fasctime(local)); return 0;
# u" ?' \$ [$ k& K} ( z% B6 O) ]$ W5 N+ J3 |5 v
/ _; ]8 c4 X& ?, L
函数名: drawpoly 
6 `( |0 C) r& A+ Q$ b# }功能: 画多边形 , o5 o$ P7 C% d+ |7 m9 B" \
用法: void far drawpoly(int numpoints, int far *polypoints); $ X0 H, A: ^1 W* }9 `& i0 i' p5 R, r
程序例: #include <GRAPHICS.H>6 e4 ~8 a. L2 u
#include <STDLIB.H>, _8 }9 C) }/ d$ @4 B. w
#include <STDIO.H>
6 W; D6 g! S$ ^ V& w- R' ?#include <CONIO.H>int main(void) + J9 l% |$ l- J7 j
{ 4 V/ ]% W( y/ \2 A. x# R4 [- |
/* request auto detection */ # m7 p1 t' d0 @4 _4 E; ~
int gdriver = DETECT, gmode, errorcode;
9 i. Q& V. n$ A M2 ?2 nint maxx, maxy; /* our polygon array */ 6 T5 u% ?6 P. N( B5 l( M
int poly[10]; /* initialize graphics and local 2 a5 _0 o! B1 J$ X2 E
variables */ # J( h! h- v' [2 i- R
initgraph(&gdriver, &gmode, ""); /* read result of initialization */ " ^) @7 }- ^- a- d; d6 Y- x! X
errorcode = graphresult();
- H4 J, b ^. D5 \4 Zif (errorcode != grOk)
# ^* y- S% [6 E* m& o/* an error occurred */
9 a9 i+ V5 E; \1 _{
; k2 P3 P$ J5 {printf("Graphics error: %s\n", \ / Y+ p) \$ t. _: f' |; I# \$ d
grapherrormsg(errorcode)); 5 |7 K. v: J+ y M7 R6 j
printf("Press any key to halt:"); 7 \* ] H$ `' ]
getch();
! r* u5 B8 a( _3 E$ w/* terminate with an error code */ 9 d6 ^; V1 |* {6 }* e6 h
exit(1);
9 {) T" U% |2 n6 d- H! z, Y$ b. z} maxx = getmaxx();
6 c+ ~, y& a0 R6 dmaxy = getmaxy(); poly[0] = 20; /* 1st vertext */ 5 M( z! F3 c, ~
poly[1] = maxy / 2; poly[2] = maxx - 20; /* 2nd */ 6 b, v$ B' ~ o1 o0 d; C, ~- O
poly[3] = 20; poly[4] = maxx - 50; /* 3rd */ ) M5 O% p9 _2 Y2 @1 @
poly[5] = maxy - 20; poly[6] = maxx / 2; /* 4th */
 Q- w h4 T C; Q- v; l- Fpoly[7] = maxy / 2; 3 U' |, P: p) ?* m+ g' k1 h
/* - m: F4 l" t* a# A( N9 ^
drawpoly doesn't automatically close
8 m8 ~0 G P9 U, ?5 X1 ~1 Ithe polygon, so we close it.
9 K* S7 o) J! [2 z! d6 h*/
2 z1 r, Z9 m* E/ Q& x& T' ]poly[8] = poly[0];
* T- H( ^0 e: j' w! r$ A4 lpoly[9] = poly[1]; /* draw the polygon */ 5 }' H, c' |+ G5 a" E( l
drawpoly(5, poly); /* clean up */ }7 E5 S. {$ U& a$ Z6 c
getch();
( Z7 U) `5 d; u7 e- bclosegraph(); ' d! z. x2 L2 u
return 0; 3 h! w8 X9 q" i2 b6 y/ Y, }
} |% I% z7 w# Q: Z! x: J+ ]
* W* P4 N4 J# F" J' y, y
函数名: dup 
+ m. P- H- U ^& w% j7 ?& }4 k功能: 复制一个文件句柄 . H2 A; O, ^" A; ]
用法: int dup(int handle); ! H8 t9 M6 }( ~& Z8 b
程序例: #include <STRING.H>. |) R4 [5 @+ l+ V. A' a* W4 C7 J
#include <STDIO.H>
3 N( ?6 w! ^- }9 u0 D6 H#include <CONIO.H>
8 y7 ^+ p N: `& m; X$ D, P" J#include <IO.H>void flush(FILE *stream); int main(void)
! O' `; D: x0 u: b9 Z8 \{ 2 j( l l, l9 p; J' B% [9 N
FILE *fp;
3 U/ M a% t! v# H) Ochar msg[] = "This is a test"; /* create a file */
5 P; `9 q9 M* n4 @+ b* X* Wfp = fopen("DUMMY.FIL", "w"); /* write some data to the file */ / d& T( v0 [9 t; m5 @( @" b: P
fwrite(msg, strlen(msg), 1, fp); clrscr();
6 v U% \( C/ ^! i+ E( Vprintf("Press any key to flush \ ( n P# H2 F& G4 K6 m5 R! R: S9 J
DUMMY.FIL:");
9 x, e F: N4 a: Jgetch(); /* flush the data to DUMMY.FIL without
2 x( U0 D9 }7 bclosing it */ ' d* _( i+ }' o, X8 G4 E
flush(fp); printf("\nFile was flushed, Press any \
- N# N5 q* E6 I( Lkey to quit:");
( v! F8 p' i9 a, F- Ygetch(); 3 ]( o2 y! u5 E' ^: K3 N
return 0;
5 S* p% i' e: A! u} void flush(FILE *stream)
( \ [) I5 B3 o{ : i" ?8 m2 ]+ z% k3 B$ `
int duphandle; /* flush TC's internal buffer */
- Z3 Q D u7 S |/ ]. a( Kfflush(stream); /* make a duplicate file handle */ 3 ?, q/ q9 x1 B7 p. \
duphandle = dup(fileno(stream)); /* close the duplicate handle to flush the 5 Y: H' I$ H4 H- P) Z( b- D
DOS buffer */
! p% P3 h, J) bclose(duphandle);
: z* a' {% J, [" u% ~8 E) i} 2 L3 r0 q& J) r
0 L6 g3 ?) ]5 J, s) V5 D
函数名: dup2 
# h; d% ^$ p3 _, m/ V/ l$ q3 l功能: 复制文件句柄 # D: C1 ?. w3 r) v1 R3 I; \7 i& V$ U
用法: int dup2(int oldhandle, int newhandle);
( E1 b- @, Q. j5 X- w0 w4 @程序例: #include <SYS\STAT.H>
) g: p) w3 K' F+ h#include <STRING.H>; A. L! s& B7 q% f( ~- s# ]
#include <FCNTL.H>
, S1 G) J+ M5 V4 V6 j/ }2 z3 B8 U#include <IO.H>int main(void) , r$ g5 t" S) G) q8 x0 j
{ : v* O+ w( M! x' [
#define STDOUT 1 int nul, oldstdout; 5 E/ G0 K# N7 v
char msg[] = "This is a test"; /* create a file */ % P h$ j' C" S* }% ?2 p9 y
nul = open("DUMMY.FIL", O_CREAT | O_RDWR, ) {/ B. W% O% I* Y' Y
S_IREAD | S_IWRITE); /* create a duplicate handle for standard
8 j0 |. i) ^3 g2 poutput */ ) _1 r; E- I* Z& Q- Y
oldstdout = dup(STDOUT);
 a& X! Z/ z) Z; X" M/*
% |# j. m8 g. J4 I0 g9 r+ aredirect standard output to DUMMY.FIL ( o0 y( M3 y3 {8 e x
by duplicating the file handle onto the " e# P% ^( ?% J1 n" k/ [. f: R# c
file handle for standard output.
# F: D& w1 m3 Z2 ]*/
! N. p$ \# I ]dup2(nul, STDOUT); /* close the handle for DUMMY.FIL */
. g0 T5 t7 D! Z+ {7 ]close(nul); /* will be redirected into DUMMY.FIL */
' ~8 L& ^! X3 nwrite(STDOUT, msg, strlen(msg)); /* restore original standard output
" C9 f& J; [0 C2 [ \5 Lhandle */ / c* B0 {) ^6 Q3 l
dup2(oldstdout, STDOUT); /* close duplicate handle for STDOUT */
+ x& w' S, M" R+ O. P0 n+ `. Qclose(oldstdout); return 0; 0 k% c4 O$ {$ x( S$ u0 ^
} 8 b5 V) Y `9 |/ Y1 ^! {4 o


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