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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); 
* I$ N/ P7 m5 Q* Q% iprintf("About to exec child with arg1 arg2 ...\n"); / q/ X! M& g4 ^$ E: L% f
execv("CHILD.EXE", argv); 
4 A/ c S) g+ d. H8 rperror("exec error"); 
$ c2 D9 H! p% T2 ~+ Aexit(1);
( @5 s" H2 w. X% z, K9 @4 s8 H# ^# U} 5 t5 |6 J) M- w4 J( @
4 M# H6 E+ L9 A6 A9 ?

8 R# Z* j5 O. r! L' N函数名: exit 
% K( @- F2 \! ]% P" z- _. e功能: 终止程序 % N& c$ v. Z# u+ _ V! H3 t
用法: void exit(int status); ) _6 z! r. z, u/ e' Y
程序例: / [9 g1 K& Y f
#include <STDLIB.H>
. }2 n* r- m, v1 ^3 M. E7 {#include <CONIO.H>
2 K1 B! d! x# c, j- G; R#include <STDIO.H>
$ s* b& I/ k2 t7 k9 ^7 B& r0 |int main(void)
1 g* n7 h l u{
$ r0 l* O `) Q# c! q( xint status; * v# ~0 a2 N- `2 t V# z/ E$ T; I
printf("Enter either 1 or 2\n"); 5 |7 y K5 ?# W. K& F( e" g3 M
status = getch(); . m" b/ s3 H G6 d* Z
/* Sets DOS errorlevel */ : e8 ~6 ^/ r3 J+ Y; P$ s G
exit(status - '0'); 1 g# Z ~4 B' w \& i# E q5 V
/* Note: this line is never reached */ 4 ]( D# ]0 Q G3 v3 ^) g
return 0; * @" l9 }& r5 N8 m+ v, S5 M1 R1 s0 H
}
- e" l5 r0 E2 t! q8 v
$ X! R* _2 p* [7 \. ^# R! l' m
函数名: exp 
: L8 [2 A1 j) J" r/ R( ~功能: 指数函数 9 g# j# S5 R. U
用法: double exp(double x);
$ @1 h- {6 }+ E! _. Z& ~程序例: 
5 B2 Q' v3 l& h8 N. X# f#include <STDIO.H>% o" s* {) C% `2 s% U% w a/ v
#include <MATH.H>
$ i& x; [1 V# pint main(void) g* I5 f% s, F; M/ L) h
{ 4 y9 b) L# E$ e; ]2 Z' g9 |
double result; 8 v, E8 @; C" }- L% R* g6 f* e: {$ [+ N
double x = 4.0; ! x! Q1 c- x0 H0 W
result = exp(x); # Y* U" X8 S D& {4 u" j
printf("'e' raised to the power \
1 z6 @- ^! k( F2 A2 yof %lf (e ^ %lf) = %lf\n",
/ [( Q# h# _' A7 ]4 p2 U4 d( _* yx, x, result); 
& t7 Y1 i, E3 d4 ]' v) ^return 0;
7 ?+ r5 K- a" [" ~) p$ Y}
) S0 j* G4 `2 d
作者: 韩冰 时间: 2004-10-4 03:02
< align=center>函数大全(d开头)$ s& T7 \" u6 Q. ~
+ k8 s6 v; }! u; R
<>函数名: delay 
' L8 A" K6 }: A- ]8 i" A ^功能: 将程序的执行暂停一段时间(毫秒) : S |9 W, u& H) a/ v
用法: void delay(unsigned milliseconds); ( m$ g3 v3 v$ S+ @
程序例:
( P, M- X/ s2 k, N1 G/* Emits a 440-Hz tone for 500 milliseconds */
5 N8 Q) ]) i2 r1 s4 \6 k#include <DOS.H><>int main(void) / v4 Y+ Y; r; u
{ * ~8 j# A, ^) ]- a) r* o
sound(440); 4 o' O! E: B" N7 z
delay(500);
9 c! I; p! M6 N, Lnosound(); <>return 0;
4 G2 V1 ~4 |% U" ]! S" O# r3 z' [}
3 A( d$ c6 T7 A) t9 ?& R! d+ _; f3 F) {8 k
<>函数名: delline 8 K6 X" R6 P8 n/ q& }4 r" Z
功能: 在文本窗口中删去一行
1 Y; P1 q& T3 f0 I' \用法: void delline(void); 2 k/ m- d6 @' }& _% o) v/ b" V
程序例: <>#include <CONIO.H><>int main(void)
: U- F! A, B T0 l+ M0 R2 _5 N{
6 Z; ]' w5 ?$ \- w3 F8 tclrscr(); / y' b8 q9 ?4 y& g1 X) P
cprintf("The function DELLINE deletes \ ) h8 @& {4 T- ]& i3 ^! m9 ~
the line containing the\r\n");
2 c4 L( V. {& C+ I/ }- m9 Ocprintf("cursor and moves all lines \ 4 S3 u" I& Z3 `4 U
below it one line up.\r\n");
2 ^6 s0 o6 s) m. X/ k3 tcprintf("DELLINE operates within the \ 7 V ~ b8 F5 i9 {7 }
currently active text\r\n"); ' }" r8 b% A# x8 @1 N
cprintf("window. Press any key to \ 9 m2 e# h) ?' P
continue . . .");
* ^& J3 ?! V: P8 ?% ~* lgotoxy(1,2); /* Move the cursor to the
. R$ K! h6 D" p4 I9 l" csecond line and first column */
( K* n, t5 w2 a7 h# Lgetch(); <>delline(); / [ r1 K+ w& h! N! }
getch(); <>return 0;
& _" |: [2 K- F, p4 b) ~} , D& n; p3 [. ]- r, U
<>函数名: detectgraph 
( k2 w' e/ b" d# L5 m功能: 通过检测硬件确定图形驱动程序和模式
" r# I9 ?* w2 s- `1 K7 W/ G, c用法: void far detectgraph(int far *graphdriver, int far *graphmode); * S$ k: L3 M4 W: E8 U5 y0 N- v f
程序例: <>#include <GRAPHICS.H>
$ Y0 C9 h& n, i- p+ T/ T#include <STDLIB.H>- j6 ^' f& T" O1 @2 _6 R2 F% f- s
#include <STDIO.H>* k6 V2 a- _* h1 D
#include <CONIO.H><>/* names of the various cards supported */
; T1 b k9 `) C! T3 d% m4 Xchar *dname[] = { "requests detection",
 u# ?7 m7 w s"a CGA",
- J* j0 a8 [& z* s/ @"an MCGA", , `0 G1 t( l4 m' h/ E: _1 i: E
"an EGA",
, V o3 ~2 H2 m" O9 X" r"a 64K EGA", # P1 w. ]7 ^' |1 u- i
"a monochrome EGA",
2 C8 \6 U7 o4 q! D$ H( Z"an IBM 8514",
7 ^( L0 L/ f+ \"a Hercules monochrome",
8 b9 O6 p; w) h. T/ |0 ?"an AT&T 6300 PC",
2 m* W! E, k) a) P/ R"a VGA", 1 D1 M* q- A5 s2 C5 D; Z `
"an IBM 3270 PC"
# [) w- E2 A1 a& C% f0 H, S}; <>int main(void) ; }. f2 I/ r g+ v+ x8 C" A
{
6 j- c: v" [' b8 l* H1 i3 X1 @/* returns detected hardware info. */
! D' P& l5 e/ W1 nint gdriver, gmode, errorcode; <>/* detect graphics hardware available */
( h/ o( b+ r d* Z7 E0 l4 Cdetectgraph(&gdriver, &gmode); <>/* read result of detectgraph call */ 4 m9 ~9 @4 m( [- e2 j5 W. G
errorcode = graphresult(); ! I) J$ ^$ ^" f# P
if (errorcode != grOk) /* an error 5 F4 N( J' G* _/ s1 ^5 {
occurred */
3 Y) K1 z+ ~5 h+ l0 H: C2 i7 D{
' w8 V3 q- X$ h- N1 v' N$ }printf("Graphics error: %s\n", \ 5 E7 ^' d7 l6 \/ l$ ]8 ?' i
grapherrormsg(errorcode)); : M+ y8 Z, j7 V, \' \4 O
printf("ress any key to halt:"); & D- X& t, n7 \; W
getch(); ' `& C# P M( S/ D W
exit(1); /* terminate with an error
6 T5 ~8 k9 D/ B: hcode */ - {% x" x+ [ B( D) c! E A
} <>/* display the information detected */ & P& H$ f" ]! Z
clrscr();
* n7 t2 f& I9 x3 ]printf("You have %s video display \ 8 k5 v) {, }5 }; V, X9 n, B+ N
card.\n", dname[gdriver]); . c) t/ O+ t8 O: T$ `
printf("ress any key to halt:"); 2 c: ^' z2 s4 c/ B: q/ Z
getch();
/ Y* O7 ^$ L; C, i% W; ureturn 0;
+ i8 h7 v- T; x6 j1 ^} 2 M% M# n1 I& W% o

6 {5 k% D- g9 s+ d# i2 O D- H) y1 |- d$ p
<>函数名: difftime 
% o1 W Y6 ~# V+ O功能: 计算两个时刻之间的时间差
1 @3 y5 M# G6 f( K1 \$ s$ l4 o2 T用法: double difftime(time_t time2, time_t time1); # `; O% b; [9 X4 N$ r
程序例: <>#include <TIME.H>
) u) v" \! `5 n1 @ L#include <STDIO.H>: O; t% {+ p$ Y+ e
#include <DOS.H>
5 D# k2 i0 M2 V#include <CONIO.H><>int main(void) 2 _# _- G: ~% F8 V6 c# m
{
- z4 ^: ~# u& Ftime_t first, second; <>clrscr();
 ]5 l7 s' j5 ]# j; ]4 @ rfirst = time(NULL); /* Gets system 1 {+ F4 Q, m' x0 S S0 F
time */ |% k( [0 S7 s4 L5 l
delay(2000); /* Waits 2 secs */
& D. x1 _' _& P( M! `! C8 j: Isecond = time(NULL); /* Gets system time
( d3 h, Q2 p0 [1 k% Tagain */ <>printf("The difference is: %f \
; c6 n" A9 \ W' W# \, E: v. b1 @1 Vseconds\n",difftime(second,first)); & A. J7 @; }# o' G& ~6 r
getch(); <>return 0; : u2 t1 N' s3 |- Z& a2 Z3 a: n
}
5 {- v& _: G0 l# h _: R2 W' x" z" E2 \( w& P; k# A' M
<>函数名: disable 
 q9 U: \1 x2 q; V0 M* z' M6 i功能: 屏蔽中断 * b& j4 r2 ]) f
用法: void disable(void);
6 v( g1 O- a9 x程序例: <>/***NOTE: This is an interrupt service 1 E* F$ w7 [9 S$ q! O0 X2 g Y
routine. You cannot compile this program
/ N( F: @. u. P# \2 ~/ }2 M5 `& Ewith Test Stack Overflow turned on and
) s: c! W, m8 z1 |get an executable file that operates
$ a: J( K! w) g7 A! X$ lcorrectly. */ <>#include <STDIO.H>
0 i( {7 V; E8 k) n/ a% L* @#include <DOS.H>: O w# f$ A1 z/ I V
#include <CONIO.H><>#define INTR 0X1C /* The clock tick : j d, S* O' }5 J2 s& J3 G
interrupt */ <>void interrupt ( *oldhandler)(void); <>int count=0; void interrupt handler(void)
: g5 R; l/ j2 H1 V" z, K{
2 ]: F* z# c, j% R M/* disable interrupts during the handling of 8 f: J. P+ H2 F9 J
the interrupt */ / {" R6 \9 Q5 ], O+ R7 B4 `, X
disable();
/ h1 _" V/ K9 d7 V" V/* increase the global counter */
/ F* R) C6 d4 s# W2 \count++; 1 }9 p% f+ f! Q" } J) q
/* reenable interrupts at the end of the , @$ ]8 W4 I1 k( \; s8 x
handler */
5 ~( M( K: u7 q! z# f* \, henable();
) A) p$ b% _$ T% V1 N) E x/* call the old routine */ - l- @+ [) E6 r& d5 {
oldhandler(); & x0 h/ {3 D! k( p# X5 _6 H
} int main(void)
0 h& q* {! n6 A- e0 h& f{
/ j0 |7 T0 w! b D: h/* save the old interrupt vector */
: n; b* `7 h4 g0 c, U ~3 y9 zoldhandler = getvect(INTR); /* install the new interrupt handler */ 9 F5 y1 S3 s5 N/ L( c2 Y
setvect(INTR, handler); /* loop until the counter exceeds 20 */
- E% p# {$ C2 O1 ^5 Vwhile (count < 20) . u# l5 h* v0 k, |. c9 ~
printf("count is %d\n",count); /* reset the old interrupt handler */ % r6 s/ _& [, \# v; D' B4 k
setvect(INTR, oldhandler); return 0; 2 l* ~9 j- ], D c& p1 B
} 函数名: div ' e# c# d n/ a- g) {' I+ b+ ^, E
功能: 将两个整数相除, 返回商和余数 8 ^/ Q& I2 s" w. X ~4 K2 V4 f
用法: div_t (int number, int denom); 6 N8 z- a$ l8 J( j
程序例: #include <STDLIB.H>
) t3 I3 t/ d1 q& G6 U; l#include <STDIO.H>div_t x; int main(void) 3 D: B* r" v- T7 U3 J" M/ \
{
0 A& X0 ~$ P2 ]" cx = div(10,3);
1 Q. H, Z9 l6 Y" I" f+ n% Lprintf("10 div 3 = %d remainder %d\n", x.quot, x.rem); return 0; 4 x7 q* J8 M! h! n2 \) P; i, T
} ) ]' R, r9 r( c1 }
; G( u5 A7 z3 w; B g4 e# a
函数名: dosexterr 6 d* B$ K2 z9 C5 a
功能: 获取扩展DOS错误信息 ! x2 S \7 g& ~9 c
用法: int dosexterr(struct DOSERR *dblkp); , j# P" ?( @, R
程序例: #include <STDIO.H>! E4 e1 F7 j* Y$ Z; G2 q/ ^' E
#include <DOS.H>int main(void)
# U5 P4 L8 _" D3 I1 b1 O( ?{ - O: H6 U, @0 h |$ e) W2 H6 r
FILE *fp; , Z( x; X% U. w/ I
struct DOSERROR info; fp = fopen("perror.dat","r");
7 F2 I% j* A# l8 Y3 F3 G$ ?% p7 Zif (!fp) perror("Unable to open file for
; X/ V5 e* T! c) G* [4 E! {" Oreading"); 6 c/ I1 q" s3 K6 ~. _: ?
dosexterr(&info); printf("Extended DOS error \
1 u1 `! G8 Z' F9 {9 d0 E- { X0 R( ainformation:\n"); : a8 U N g5 |# u
printf(" Extended error: \ 6 I- v, X$ ?& H7 \
%d\n",info.exterror);
: I4 z, K4 u) v3 y4 A* w( Oprintf(" Class: \ 3 K; B3 j- }; ^/ A
%x\n",info.class); & c N. K. L5 w) _6 q1 D
printf(" Action: \
' ^& Z1 x; E/ ?& e%x\n",info.action); 0 V% ?2 m. n$ v3 b/ X' p' p5 E+ I
printf(" Error Locus: \
# n& p6 m$ D* t& q3 ?%x\n",info.locus); return 0;
; v+ K0 `% U2 V8 V, D# i+ ]} 
5 o, i5 q3 n/ P( v1 [! w2 }* x. p) J3 X r6 K! W
函数名: dostounix * I+ l, S+ t' Z* h2 T6 q$ z
功能: 转换日期和时间为UNIX时间格式
7 z0 Q, T/ J4 H1 L6 f7 i6 [% ]用法: long dostounix(struct date *dateptr, struct time *timeptr); " k4 S3 _. J3 ~: g0 a$ ]7 {' Q
程序例: #include <TIME.H>
1 h W5 Y& K4 N Z" m#include <STDDEF.H>
4 I6 E- E4 H/ m `6 K: K7 \! t7 I#include <DOS.H>6 M5 F$ |6 \" u5 L5 E
#include <STDIO.H>int main(void) : l4 S* h. U; ]
{ # ^ B; D5 k& }: O$ [5 o& p+ \
time_t t;
! X; {# v8 W7 R% l4 A kstruct time d_time;
, Z# I8 s1 j( v1 `% g! I! sstruct date d_date; % P1 t% Z/ i+ x" n
struct tm *local; getdate(&d_date);
! K, _7 M! [$ R- igettime(&d_time); t = dostounix(&d_date, &d_time); + b: a1 J9 W4 [% C+ r- j) C
local = localtime(&t); - B+ q6 }0 d/ f0 R/ @
printf("Time and Date: %s\n", \ 0 v8 o: c* p+ ]( J& @' S
asctime(local)); return 0;
- q! e# {1 h* {6 B4 k, c( h# A' p} 
! P4 Q) r, v6 C3 C& Y2 j2 K( a# i/ j1 x
函数名: drawpoly " I' g9 s* r; b3 j
功能: 画多边形
8 l8 N* S+ [2 g1 z用法: void far drawpoly(int numpoints, int far *polypoints); 2 K- H9 \8 [5 o$ R, c
程序例: #include <GRAPHICS.H>
# o' d, C9 n- x) j9 b#include <STDLIB.H>
2 z1 l ?6 P1 u7 a B% y#include <STDIO.H>) G2 Q) ]* r4 |( t) }" d7 y
#include <CONIO.H>int main(void) 8 h7 O4 g6 R! b& A- w. d
{
- B) V) ?2 s x* e! k/* request auto detection */ . M- x: Q7 ]! c3 O
int gdriver = DETECT, gmode, errorcode;
) R- m. w1 p! b$ }8 B1 k$ z7 z8 fint maxx, maxy; /* our polygon array */
! G) q5 U5 Q3 s" C. c" l. X" g; m7 qint poly[10]; /* initialize graphics and local * }. L, y( P: b A# u
variables */ + \, B: a. G/ |
initgraph(&gdriver, &gmode, ""); /* read result of initialization */
4 p2 R1 {8 m) ~4 Werrorcode = graphresult();
4 g' G' L) J8 d5 E% Aif (errorcode != grOk) / y9 J5 x, Q( \" @# c! d
/* an error occurred */
( u6 _; R2 L E; q' Z{ / I" k- }1 O) O) x; |2 M X) s
printf("Graphics error: %s\n", \
" b) L$ D- o. igrapherrormsg(errorcode)); # p0 q+ b+ n& [; H: ~0 x
printf("Press any key to halt:"); - M2 n0 T: z4 b9 Q: ~% j; X% d
getch();
& |/ @$ A! G+ L/* terminate with an error code */ # x9 f9 L x Q
exit(1); / S% F& @( ]3 x
} maxx = getmaxx();
 G7 S t' p7 g. F4 p# v# A0 n9 hmaxy = getmaxy(); poly[0] = 20; /* 1st vertext */
3 [* i& y+ F% R4 k6 t j$ L% hpoly[1] = maxy / 2; poly[2] = maxx - 20; /* 2nd */
# X" S( `6 d" I+ A0 E5 }1 hpoly[3] = 20; poly[4] = maxx - 50; /* 3rd */ ! M; l$ n5 c6 A+ {
poly[5] = maxy - 20; poly[6] = maxx / 2; /* 4th */ " f* y" B! m6 Y6 r, H
poly[7] = maxy / 2;
# \$ k6 [, ~# x3 w/*
- t4 w2 I2 l# m" E4 Vdrawpoly doesn't automatically close
: S8 R( a; f4 X% h- @5 p, y; |the polygon, so we close it.
& L4 ~+ l6 `! Z3 y: }6 W& K7 t0 q: Q*/ ' L$ m: G+ k: ]
poly[8] = poly[0]; , V) A& P+ b3 @ T% {7 ^; J- x; P
poly[9] = poly[1]; /* draw the polygon */
) H2 v% d @2 Q' P1 Ldrawpoly(5, poly); /* clean up */ , R% U4 }" D5 E
getch();
' h* ~6 ^1 x$ R, T' uclosegraph(); 2 x1 r4 i5 n. o# }
return 0;
9 [2 V- C3 ^' P9 ~1 g- h3 J} * w8 @- t, `* f+ |: n I. c
1 U9 ?7 h% Y: z1 L0 {
函数名: dup ( B, g$ p8 H- u
功能: 复制一个文件句柄 ' P8 t' {8 F, I: V0 U+ F9 r3 B4 P( q* p
用法: int dup(int handle);
$ ?4 O3 A2 l7 ^6 D/ @1 I程序例: #include <STRING.H>
! y( |1 _( |( t' c/ X7 w& U w6 C% e#include <STDIO.H>0 p1 {+ e7 _4 v8 N, x V& J
#include <CONIO.H>
; X, ~: i6 \/ Y#include <IO.H>void flush(FILE *stream); int main(void)
3 \1 h0 Q/ ~2 T; F; E{
; {( ^2 Q5 P% OFILE *fp; # W- G1 K8 _' `1 j
char msg[] = "This is a test"; /* create a file */ ( v* J$ k3 w+ S3 q, T' C
fp = fopen("DUMMY.FIL", "w"); /* write some data to the file */ , h: |1 L, ]2 x+ L
fwrite(msg, strlen(msg), 1, fp); clrscr(); 4 B- X6 Y8 ~" H
printf("Press any key to flush \ + Q/ b; T: m7 l+ I* g5 u
DUMMY.FIL:");
8 w; r# u8 {! w; {9 W6 ^getch(); /* flush the data to DUMMY.FIL without
4 K B7 N, A; cclosing it */
3 _8 L4 T) T0 i8 x( W0 L3 H8 _flush(fp); printf("\nFile was flushed, Press any \ $ H' M! Q" n* |$ ~1 k& {4 k8 r
key to quit:"); 3 V3 Q l& \/ p, s
getch();
7 k5 m; S* {0 @- X& P* Greturn 0;
/ u+ @- P1 Q, s/ N} void flush(FILE *stream)
3 v8 g) i) r9 u& o{
: E) L9 j- j$ M! Oint duphandle; /* flush TC's internal buffer */ 6 U( C6 d. e0 |( X+ V3 @8 _
fflush(stream); /* make a duplicate file handle */ 4 V g. `+ h0 _
duphandle = dup(fileno(stream)); /* close the duplicate handle to flush the 5 { v6 r. n2 i8 V K/ C
DOS buffer */ , Z- P& Z6 s6 g5 q) }& O0 s& I' k
close(duphandle);
$ N% X0 G# z4 b# @5 T+ q6 U}
: ^ X4 r/ A$ q$ m) a) o* P L! h
" [5 F& b& ?- A/ o$ N/ w9 |函数名: dup2 % q) F3 m( Q l% r: |
功能: 复制文件句柄 # P7 E5 F; R/ U' K/ L2 T+ W$ ?
用法: int dup2(int oldhandle, int newhandle);
$ }% {0 s+ B. d程序例: #include <SYS\STAT.H>- b% ^" R0 t$ S
#include <STRING.H>9 ?) j2 i6 I' ]" y, P% o- X0 M
#include <FCNTL.H># q+ l" r! q7 X: Z" C: O, a" f
#include <IO.H>int main(void) % w7 O8 X( n" u$ r$ e2 p$ a
{ 4 y6 J4 v* ^/ a/ e0 e+ t
#define STDOUT 1 int nul, oldstdout;
1 g: C' N3 X* W- v& X! k2 schar msg[] = "This is a test"; /* create a file */
% F- M; `5 _. J" xnul = open("DUMMY.FIL", O_CREAT | O_RDWR, " L* O$ N+ c( x3 q
S_IREAD | S_IWRITE); /* create a duplicate handle for standard ! {2 Z. ^# P6 W! ~; H) d
output */
8 ]" u* P7 n% B$ a7 N# Toldstdout = dup(STDOUT); ) e- O" F g$ k ~
/* 0 d* N; V# X" W: N: @$ K
redirect standard output to DUMMY.FIL & h# R/ `. h4 t7 F# P
by duplicating the file handle onto the
! q0 }0 _0 R2 O" l& tfile handle for standard output.
, p( ~6 a9 ~5 R*/ 7 f6 l# m4 J2 A5 @: M
dup2(nul, STDOUT); /* close the handle for DUMMY.FIL */
( `& N7 @7 r* q, k; s- d( B3 Tclose(nul); /* will be redirected into DUMMY.FIL */
7 h2 e1 Z, l% L7 owrite(STDOUT, msg, strlen(msg)); /* restore original standard output / M; i, U% \3 r! q, |. b( N
handle */ , N% h9 D0 Z: |/ B
dup2(oldstdout, STDOUT); /* close duplicate handle for STDOUT */ ! a3 V* i' u% P# f) u+ o
close(oldstdout); return 0; 3 }# j: A; D$ ]4 {" U* d6 \& L
} 4 ?$ N7 M& e+ _. [& f


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