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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); K/ B+ A9 v" G4 a* g) `* H
printf("About to exec child with arg1 arg2 ...\n"); $ J4 {+ T9 l( z6 F& D
execv("CHILD.EXE", argv); 9 M$ R) N, k2 a \# n6 ?! }0 o
perror("exec error"); , h" g/ U! J# V. h/ N
exit(1);
/ p7 o! r! h! M: x6 [}
; d1 F: i0 ?+ ?8 N, m4 k* W5 d& R" S5 X6 x4 e3 }; J

# E& y3 ~) c1 R. P函数名: exit 8 C& t; I2 {* A7 v- W8 F
功能: 终止程序 2 m! B% f7 U) o/ q
用法: void exit(int status); 6 ~- e8 k/ E# `. j8 i1 F- g" j- n
程序例: I7 t6 \8 ~" ?8 Y: b2 V
#include <STDLIB.H>
! {$ K: O3 q5 F$ K( \#include <CONIO.H>
% A* N C1 W6 ?#include <STDIO.H>
: R: n7 g- l7 Xint main(void)
2 n1 ?5 e- b& g) B* c- q{
, e$ @2 n6 v7 L1 v, v, o8 }int status; 
. \0 c8 d1 s. E6 S6 s; w! `$ Yprintf("Enter either 1 or 2\n"); " N8 @( M6 V% G, W$ }1 c
status = getch(); # r% ~# F7 M0 ^$ e
/* Sets DOS errorlevel */ , @( w& p3 [0 T
exit(status - '0'); 
& o- i+ Y2 G8 [/* Note: this line is never reached */
( ]# Z2 `# e* g! u, E6 nreturn 0;
$ p9 k: q; K% R" b: i: g} { T8 j3 m& s. {4 d3 r- ?0 j
. x& X/ e- h6 ~ u' m! Q

$ k: G7 R7 Q0 \9 H7 {9 X2 ^8 Z函数名: exp 7 n2 C3 Q5 l8 I6 v/ t' A
功能: 指数函数
& I0 h. D8 F/ q9 i! L用法: double exp(double x);
4 A. u) L5 B& K7 o* A程序例: 
9 q4 L2 b" o+ z7 Y$ k- r0 d#include <STDIO.H>+ \! q- b" I$ A- P6 t q
#include <MATH.H>
& T/ m% x+ [9 Z6 i8 e4 xint main(void)
# i% K5 {9 Q+ x& m{
/ Z, o7 g! \+ u9 |1 u- C5 Jdouble result; 5 p# \, D2 n9 C$ B a8 i9 X& x
double x = 4.0; 9 h, g6 `. F8 r6 y/ J# s8 ?" X3 O9 Q
result = exp(x); 0 U% K# ^; A& }7 h+ b# j# p3 `
printf("'e' raised to the power \ + U% n7 E! }2 C$ k9 U' p
of %lf (e ^ %lf) = %lf\n", $ q0 e- k% H" L5 K
x, x, result); 
* X6 M O; p- _0 ?& I6 a6 z( Y1 sreturn 0; 6 l: I! K$ u& B, f6 N0 \* @% ~
}5 |5 j$ X& g7 h& `

作者: 韩冰 时间: 2004-10-4 03:02
< align=center>函数大全(d开头)
* U* y- r/ R+ m8 } u9 [
5 m9 ?2 ?' e( B<>函数名: delay 2 L1 ]7 y% X; ]: W( `, w& W H
功能: 将程序的执行暂停一段时间(毫秒)
3 @2 \& I* t/ k" e' R4 L) N* X$ o用法: void delay(unsigned milliseconds); 5 _& J/ [1 {1 O$ Q
程序例: & W% F. d/ i& I7 \, W% P
/* Emits a 440-Hz tone for 500 milliseconds */
( O$ v- H7 V0 V- w2 M/ w3 H#include <DOS.H><>int main(void) ( T. Z2 X3 j/ D) Z2 s, z8 e
{ v7 Z& B* U! g2 u4 | T
sound(440); , e* C4 a$ _& u' R# G9 i
delay(500);
! s1 X+ ]8 O& s1 Q1 xnosound(); <>return 0;
3 ^3 ^' Q3 V M" a$ W}
' @# H1 i# b! w/ ]6 {1 K- m( U m5 e; m2 n+ ^5 V2 p
<>函数名: delline ' E) g; x% `0 s% I
功能: 在文本窗口中删去一行
1 `& p1 x: A5 e! M! |! P2 |用法: void delline(void);
' n' z4 B& l3 k0 [! n/ i( c程序例: <>#include <CONIO.H><>int main(void)
, g6 p# u/ s/ `# O& e{
( }# S( W6 X: n$ h3 w; M4 Eclrscr();
/ v v1 I) D" i6 `4 T4 Ecprintf("The function DELLINE deletes \ 7 c$ z: e/ @- s/ `. t( ~
the line containing the\r\n");
& |" s7 n4 @6 K: v- Y1 [. f9 Lcprintf("cursor and moves all lines \
$ L# P# a9 E3 t+ qbelow it one line up.\r\n");
( R5 R; p$ c- g& ~cprintf("DELLINE operates within the \
1 y! C3 B ` ^. J! }currently active text\r\n"); " ]) n \* W% k$ y# j
cprintf("window. Press any key to \ : E9 \# P, A. Q
continue . . ."); / Y1 f/ W4 q7 M! f, t1 w
gotoxy(1,2); /* Move the cursor to the : t2 p/ D) V# p/ S0 F* l
second line and first column */ ! \( @8 B0 x0 W( n
getch(); <>delline();
2 [' Y9 s1 }5 }$ Pgetch(); <>return 0;
( I6 _- p+ a0 C0 i. j} 
; n% J0 b- h( K<>函数名: detectgraph " q0 G# }3 O' s
功能: 通过检测硬件确定图形驱动程序和模式
8 A% w2 v) y& X5 T, h8 X用法: void far detectgraph(int far *graphdriver, int far *graphmode); 4 {; ^7 A- I! I* J4 o8 W
程序例: <>#include <GRAPHICS.H>6 h+ ?' T! K' a4 d
#include <STDLIB.H>
* h, j: {! D& {$ ~# d#include <STDIO.H>
5 L2 |! B( H Z2 e1 p#include <CONIO.H><>/* names of the various cards supported */
4 [ F$ d* v, e O$ N8 Wchar *dname[] = { "requests detection", 1 J. A+ I7 [2 E4 w+ b V
"a CGA", + ?2 S: A P$ U5 `
"an MCGA",
, ?3 c0 p+ b Z# ^* A"an EGA", 2 i+ X1 O9 P+ s" {$ K( {' q
"a 64K EGA", 8 a% G y# b7 A" e: B. {/ H! y
"a monochrome EGA",
 w( D% F" G X6 S& \1 M& Q- G- H"an IBM 8514",
+ s8 _. l$ C/ P! x. {"a Hercules monochrome", 1 J6 s( v+ e& L' i; @7 U" r/ I
"an AT&T 6300 PC", : ]( _9 Z1 {/ {# {
"a VGA", 6 d* {& E' \( E
"an IBM 3270 PC" 2 j# w+ i/ \$ k- n, L
}; <>int main(void)
; U( I& E; k8 s0 h! m{
2 q& v8 a2 ~& V/* returns detected hardware info. */ & f, n0 h4 |) ?3 M
int gdriver, gmode, errorcode; <>/* detect graphics hardware available */ * x1 u; G, ^4 s/ n0 J8 X
detectgraph(&gdriver, &gmode); <>/* read result of detectgraph call */ + g% q* U5 m O8 n* J. X, c
errorcode = graphresult(); & x8 W/ s& H: r0 `3 q! @
if (errorcode != grOk) /* an error
1 k* A6 R5 B$ J" R# Z3 R8 Yoccurred */ : X( J# Y( b. T) Z7 T6 C, D
{ : B7 @1 e2 [% V, U; V
printf("Graphics error: %s\n", \ $ y$ K1 @/ n' x& H
grapherrormsg(errorcode));
, e" L, J# p' T/ X( Uprintf("ress any key to halt:"); * A3 \: v9 o$ Z2 r0 g3 h
getch(); 0 m# N, c0 {/ X4 a
exit(1); /* terminate with an error
2 X ~1 d& b/ y9 F: o; u! I9 @code */
0 f6 w, m3 Q# ?} <>/* display the information detected */ * d2 v5 z+ |/ l' s5 V( E7 O2 \0 j
clrscr(); 8 O! u) C" h. P% y" u( R8 r
printf("You have %s video display \ ; ~# I8 i3 q9 V6 P# k
card.\n", dname[gdriver]); ( M1 t2 q/ T( }
printf("ress any key to halt:");
0 H2 L9 f1 ~* J8 W6 Y6 L4 x; a9 Q7 sgetch();
2 D$ K/ x# ?9 v; B( N; xreturn 0; ) w5 j& w0 v8 V+ e, S$ e0 m
} 
0 C) k" U* T y' p v5 X) ~1 @, Q J# Z

$ t/ S5 V" S3 ~1 S$ Z<>函数名: difftime 
; q' M R8 [8 M) w% \: o6 O功能: 计算两个时刻之间的时间差
0 ?+ o% W' f: ]" Z$ A用法: double difftime(time_t time2, time_t time1); 0 {7 R8 g9 K: j2 p8 Z
程序例: <>#include <TIME.H>; D( b, u3 V2 r
#include <STDIO.H>
0 H4 ~& X( ]* G& d# L& P#include <DOS.H># O7 m8 N9 y. P9 R/ r8 e) q+ @- a# R5 n
#include <CONIO.H><>int main(void) 5 W; l! l0 _0 u+ ^+ R' o
{ % d: E$ o& b! ?' f
time_t first, second; <>clrscr();
! c: _0 @+ c9 m( X& @1 v& B- n( Afirst = time(NULL); /* Gets system
4 g p6 W2 K0 `' vtime */ 5 m6 t2 H" e/ b
delay(2000); /* Waits 2 secs */ * A! r( y ?# A: n" Z
second = time(NULL); /* Gets system time
9 ~) o, n. A Uagain */ <>printf("The difference is: %f \ - e7 [& `9 V5 E; t, ^3 z
seconds\n",difftime(second,first)); 9 ]$ \0 e! i7 e3 t
getch(); <>return 0;
. d. n# h; E b7 Q+ D}
! [, I4 Q7 o1 r% G5 d! m5 }* f6 t* ]: G5 S, i
<>函数名: disable / B3 m# z2 W9 D% H
功能: 屏蔽中断 * j8 ^7 x7 z8 |% l8 n3 w
用法: void disable(void);
& a k* [9 m% [, w& O! r# h8 a程序例: <>/***NOTE: This is an interrupt service . ^5 v2 o9 F& Y$ m7 C( I
routine. You cannot compile this program
4 U9 d* v/ }" d! _' R8 Swith Test Stack Overflow turned on and . H9 S& W k) l+ @+ h; F( u
get an executable file that operates ) ]9 n7 M. _, D7 T4 ]
correctly. */ <>#include <STDIO.H>
* A Z6 O0 c5 d% K( I#include <DOS.H>
, X- T4 M( {7 |# i0 u) a#include <CONIO.H><>#define INTR 0X1C /* The clock tick
/ S. U# m6 w4 f$ Linterrupt */ <>void interrupt ( *oldhandler)(void); <>int count=0; void interrupt handler(void) 1 n% ~* K4 P! T# A* V1 w: w0 R+ B
{ 5 i3 W0 l4 V% R
/* disable interrupts during the handling of ! K x7 z' m' w, U: C
the interrupt */ : V0 j9 Q* A# B4 N4 Q- P! f# }
disable();
: c7 p5 w3 p7 w/* increase the global counter */ : s: T Y. J7 [$ ]# L3 X
count++; 6 v$ r& k4 z3 _3 w( D
/* reenable interrupts at the end of the
4 N+ }- P: [( ~) A% O. b' [handler */ ! T8 m" T9 ~& A" n* Y( A) a! v
enable();
. ?* a9 G6 J: H1 J9 _/* call the old routine */ + x3 n2 P' r9 W* w0 T' U: u
oldhandler();
: c: x/ g5 ?; a9 u8 E. m6 R C} int main(void) - g& y* w. I$ V
{
" M8 j2 K8 h- }/* save the old interrupt vector */
: E" p6 h* ?, v; d ?/ ]0 g, f* ?oldhandler = getvect(INTR); /* install the new interrupt handler */
/ U! m b7 ~" q) m1 Asetvect(INTR, handler); /* loop until the counter exceeds 20 */ 6 {+ A% { F9 @5 A3 ~$ s% z+ B
while (count < 20) ; f4 I) R* U7 ]) \' i
printf("count is %d\n",count); /* reset the old interrupt handler */
# A* ~1 Z Z" G' m7 q5 ysetvect(INTR, oldhandler); return 0;
/ l2 t- m4 m) _6 O1 l} 函数名: div 2 O6 Z5 J/ C9 i1 C4 d$ o$ f
功能: 将两个整数相除, 返回商和余数 2 ]: S2 u3 a" s6 i
用法: div_t (int number, int denom);
/ L4 g% D; m/ C0 O程序例: #include <STDLIB.H>8 t+ p9 `. F( T- I) G H3 R i1 w4 I! n
#include <STDIO.H>div_t x; int main(void) 5 ?# Z+ D. f9 v% r
{
! Y* V% V: D5 }! g4 t% Ax = div(10,3);
* N- v% W$ u4 i! C) Mprintf("10 div 3 = %d remainder %d\n", x.quot, x.rem); return 0;
$ J* q% Y& g2 L; j, W- W8 t}
: `9 V) R7 P- G8 f0 y4 z, w" i( B( s, W! K$ `6 k9 t9 J% w; T) B* e# @
函数名: dosexterr . Y$ s$ S2 q/ l, S' i) L
功能: 获取扩展DOS错误信息
' g! z+ a( N. t; _用法: int dosexterr(struct DOSERR *dblkp);
" w$ r& Z1 x3 {% {2 Y0 F程序例: #include <STDIO.H>
( g% g7 q8 E5 X* o7 d#include <DOS.H>int main(void)
* i/ Y" S. @% ^* P% [2 \, k8 W q{ & Z8 @4 I" X& C) Y% ^& m) U
FILE *fp;
: F. Z7 \- s% U. xstruct DOSERROR info; fp = fopen("perror.dat","r"); 5 k, _- x+ n7 _/ x/ U, J
if (!fp) perror("Unable to open file for 1 m* T! { t# L$ R
reading");
$ J' u) I) Z2 }& \( y7 i( Tdosexterr(&info); printf("Extended DOS error \ ; X" j( t0 F6 ~$ ~1 k
information:\n");
9 O' R1 ?- A9 z$ dprintf(" Extended error: \ , r1 D, }! F9 |2 E8 M) n: b: p6 f
%d\n",info.exterror);
" {- M+ V7 q! [0 i; p" ]printf(" Class: \ ' ^( M: M" ^0 Y
%x\n",info.class);
* K8 d' z9 `$ y5 sprintf(" Action: \
+ M9 t0 w7 K* {4 Q- B7 m) w%x\n",info.action); ) i7 t) {0 R) ?
printf(" Error Locus: \ % q" w* Z/ M" I
%x\n",info.locus); return 0;
+ V7 n1 }; D% H% J. T} 
7 Y1 }9 }, s+ W' U" b
. P% b! g' N5 b. y0 O函数名: dostounix 0 e& i' S! f1 y U7 g+ J2 Q
功能: 转换日期和时间为UNIX时间格式 : [, p+ V& B. v+ C+ M) i
用法: long dostounix(struct date *dateptr, struct time *timeptr);
( X; p, p/ e) j& P+ Q程序例: #include <TIME.H>0 u e; ]7 r4 U0 z; n# C
#include <STDDEF.H>
4 p9 B3 I3 M; E0 i#include <DOS.H>$ h" Z9 C( f5 m; g0 w# E+ q# y, c9 i
#include <STDIO.H>int main(void) 8 Q" J- G: y* u0 b" k
{ 8 t' N- j: h8 M8 t3 D$ I& J. a
time_t t; ; Q" i2 W6 y2 {9 Y0 C$ V! g! f% R. `
struct time d_time; , G7 i; W. F- n* u3 W! O$ z2 t+ F
struct date d_date;
$ ?0 m" R5 j. S% {struct tm *local; getdate(&d_date);
7 j! Y4 c7 Y. A: B5 k/ wgettime(&d_time); t = dostounix(&d_date, &d_time); T* i4 W$ Q* P o
local = localtime(&t); / ]0 K' t- p2 k3 q! D
printf("Time and Date: %s\n", \
+ d8 W* m, T: G7 Z" s( j5 k- w- Nasctime(local)); return 0;
, M+ w$ q6 d+ e4 {; f# a} 9 d; F* U* h( Z# R* Z N
. R1 g/ I6 ^; U, M& p, _" @% v
函数名: drawpoly . P. Y: W5 @0 C
功能: 画多边形 1 `4 M# V# H9 s1 O- ?8 K, @7 [9 D
用法: void far drawpoly(int numpoints, int far *polypoints); 5 L1 n! q3 P4 `! L0 T) t0 J
程序例: #include <GRAPHICS.H>) r, E F# P, f: s; F8 U
#include <STDLIB.H>
/ Z+ f# s) k: U) h#include <STDIO.H>
$ t3 F. B1 Q+ G2 [#include <CONIO.H>int main(void) 5 J. B, o2 B. D! e2 H
{ I$ ^" ~/ G6 u) O }8 @/ O
/* request auto detection */ ; p8 b8 j( w2 W) u5 _* \# h0 O
int gdriver = DETECT, gmode, errorcode;
+ f* d, K" l8 t$ x* J/ pint maxx, maxy; /* our polygon array */ + a* {5 `1 b" u3 U
int poly[10]; /* initialize graphics and local ; L6 A: ^6 t( K0 h) C: m+ `
variables */ % i& k; Z+ g" Q" ~. ?+ `
initgraph(&gdriver, &gmode, ""); /* read result of initialization */ % ^. N' C' c" r ]9 f
errorcode = graphresult();
8 j4 d- K3 J9 S2 v5 t8 oif (errorcode != grOk) p# O: {: { z4 X
/* an error occurred */ $ l4 y: v) e7 Z
{ 3 b2 N; N2 H1 j6 V8 j7 D" e
printf("Graphics error: %s\n", \
8 \3 x# S/ U7 p1 @' C6 c' j& p* [grapherrormsg(errorcode));
7 J, N! f, L0 I& r/ Uprintf("Press any key to halt:"); - j5 ^# b% S) ]5 F% Q
getch(); 8 B* g' O3 ~5 ]% t+ B
/* terminate with an error code */ / _# E4 N6 i2 i( Z: K
exit(1);
& o% ^2 h! E# \ x} maxx = getmaxx(); - m- @# ^+ R: m) s7 g' t- }
maxy = getmaxy(); poly[0] = 20; /* 1st vertext */ ! w& `. b2 i" R- z
poly[1] = maxy / 2; poly[2] = maxx - 20; /* 2nd */ 9 O3 f' f' ]$ [# a
poly[3] = 20; poly[4] = maxx - 50; /* 3rd */ : y$ R4 m: \2 {8 G# i
poly[5] = maxy - 20; poly[6] = maxx / 2; /* 4th */
2 E# G; z" y, z x7 Lpoly[7] = maxy / 2; 6 G5 [# \! { W* Y
/* ^; a# R( N' J
drawpoly doesn't automatically close
5 k: X9 N, ]9 d4 i' X5 u% O/ \5 Pthe polygon, so we close it. ; @' G7 N' N8 N3 A$ f' K
*/
+ l! \7 p# ?' Y1 F* `* T- H: Gpoly[8] = poly[0]; 1 Y& Q4 q, ^' `3 y# o2 n
poly[9] = poly[1]; /* draw the polygon */
+ O; p% l+ k9 G F# wdrawpoly(5, poly); /* clean up */
8 i; v( }# }4 R: o; Zgetch();
3 F; {+ p9 [8 ?5 y; r' mclosegraph();
4 e" Z& k f- k2 Preturn 0; 5 r* V1 r( u& H) E: C
}
9 k- j% K# p% S+ d
函数名: dup B; [, g! D( o$ O( z; {# r" K
功能: 复制一个文件句柄 9 ~% V. G- E9 \ r
用法: int dup(int handle); 2 ]$ R$ a% O* Z+ X+ o6 D
程序例: #include <STRING.H>
5 u" x7 h5 j y U" N+ s/ S7 t#include <STDIO.H>: R! H: |5 P' M, J' A7 b9 W
#include <CONIO.H>
0 S. q4 o# f9 |* r#include <IO.H>void flush(FILE *stream); int main(void) ) S) j2 v; k& t) f2 F+ {
{ ) W3 S6 ^8 K8 j8 |+ _
FILE *fp;
, w" v2 m0 X$ v Z3 t7 s4 R2 q6 Wchar msg[] = "This is a test"; /* create a file */ 3 r6 o, o3 l8 a: G9 E- {
fp = fopen("DUMMY.FIL", "w"); /* write some data to the file */
. O: H$ }# |9 f" e' P% Qfwrite(msg, strlen(msg), 1, fp); clrscr(); 1 s W" {" }7 ]& I }- `$ t
printf("Press any key to flush \ . [7 `; ~; g7 N: c1 C; w
DUMMY.FIL:"); 4 f4 y' V" J: H6 b: @! [. K
getch(); /* flush the data to DUMMY.FIL without / g/ C8 a% B- U5 I. s$ T) T
closing it */ & T& s7 r/ q& Z. r4 D
flush(fp); printf("\nFile was flushed, Press any \
 \6 ^5 A4 I6 t7 a lkey to quit:");
( R; ~6 }/ k0 c" Y# E4 M1 n Q/ y) Cgetch(); ! f% ^* M6 x9 u" v# U
return 0; ! N: {& }: e% d* r2 a
} void flush(FILE *stream)
. Q, o9 P+ B2 _1 a9 j{ - n# g, u2 y: q+ i& P
int duphandle; /* flush TC's internal buffer */ / ]+ T0 |. S( N3 i# U& @6 c# Q! w
fflush(stream); /* make a duplicate file handle */
 p& }, @- C# d: ]duphandle = dup(fileno(stream)); /* close the duplicate handle to flush the / l7 o5 q; {0 b4 A" H/ h+ W, h
DOS buffer */
3 ?& k! A8 ?* v0 y$ D8 n; x7 Eclose(duphandle); / i$ W) N3 W! o
}
: Q5 r2 C; [0 S- ?4 U2 K& s3 @' K! P' @2 ?* y, p
函数名: dup2 _% a+ ?9 u# a8 a/ M; R
功能: 复制文件句柄 1 t, \+ m' V$ c7 e r# D
用法: int dup2(int oldhandle, int newhandle); : k* u! h/ [: m7 J9 f$ m6 O
程序例: #include <SYS\STAT.H>
) m$ J& t2 _4 Q2 c4 f; t#include <STRING.H> R4 s, v8 {0 H0 u: s" y; I
#include <FCNTL.H>' }0 i" W* y6 w/ K
#include <IO.H>int main(void) * S) T- B, `3 A" m7 T+ T5 ?
{
' g3 e4 g( N4 g- ~) F* l#define STDOUT 1 int nul, oldstdout;
9 A" p- L0 _. i, M4 ^char msg[] = "This is a test"; /* create a file */ 4 z. f- f: r) b) E" t+ ]& r+ O2 |
nul = open("DUMMY.FIL", O_CREAT | O_RDWR,
# U) S# F# [. I- Z) D" J# ?7 Z! nS_IREAD | S_IWRITE); /* create a duplicate handle for standard - V; C2 d, |+ V9 P5 k! D4 U. X
output */ * M+ k+ ]1 Z m. n- L- g8 G$ I
oldstdout = dup(STDOUT); 3 W/ b, x1 m' j
/*
% E7 M# n' i7 c1 q0 n# t! Nredirect standard output to DUMMY.FIL G( T4 k1 \& r9 L/ O/ T u6 S
by duplicating the file handle onto the
0 ?7 _5 I6 ~9 x& rfile handle for standard output. % s$ V$ u; Q" j
*/ 3 `5 x* E/ Y6 b2 [
dup2(nul, STDOUT); /* close the handle for DUMMY.FIL */ 6 j+ `9 t: }6 T" S0 E; [, W, `7 s/ Y
close(nul); /* will be redirected into DUMMY.FIL */ 6 C& c" r( Y/ @, w/ ?# n) k
write(STDOUT, msg, strlen(msg)); /* restore original standard output
. E! v+ \8 X( M$ q7 F) rhandle */ 0 d2 T6 a$ x; J- V& w. _
dup2(oldstdout, STDOUT); /* close duplicate handle for STDOUT */
+ o0 `% ?9 X2 f+ O1 ?close(oldstdout); return 0;
% z0 N( U4 q7 K$ n" T/ I, X}
/ v1 p) E, J; G1 G4 N* q) L

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