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Linux教程網 >> Unix知識 >> 關於Unix >> C語言庫函數---unix常用系統調用---使用說明(下)

C語言庫函數---unix常用系統調用---使用說明(下)

日期:2017/2/28 11:26:13   编辑:關於Unix


函數名: setjmp
功 能: 非局部轉移
用 法: int setjmp(jmp_buf env);
程序例:
#include ;
#include ;
#include ;
void subroutine(void);
jmp_buf jumper;
int main(void)
{
int value;
value = setjmp(jumper);
if (value != 0)
{
printf("Longjmp with value %d\n", value);
exit(value);
}
printf("About to call subroutine ... \n");
subroutine();
return 0;
}
void subroutine(void)
{
longjmp(jumper,1);
}


函數名: setlinestyle
功 能: 設置當前畫線寬度和類型
用 法: void far setlinestyle(int linestype, unsigned upattern);
程序例:
#include ;
#include ;
#include ;
#include ;
#include ;
/* the names of the line styles supported */
char *lname[] = {
"SOLID_LINE",
"DOTTED_LINE",
"CENTER_LINE",
"DASHED_LINE",
"USERBIT_LINE"
};
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int style, midx, midy, userpat;
char stylestr[40];
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
midx = getmaxx() / 2;
midy = getmaxy() / 2;
/* a user defined line pattern */
/* binary: "0000000000000001" */
userpat = 1;
for (style=SOLID_LINE; style<=USERBIT_LINE; style++)
{
/* select the line style */
setlinestyle(style, userpat, 1);
/* convert style into a string */
strcpy(stylestr, lname[style]);
/* draw a line */
line(0, 0, midx-10, midy);
/* draw a rectangle */
rectangle(0, 0, getmaxx(), getmaxy());
/* output a message */
outtextxy(midx, midy, stylestr);
/* wait for a key */
getch();
cleardevice();
}
/* clean up */
closegraph();
return 0;
}



函數名: setmem
功 能: 存值到存儲區
用 法: void setmem(void *addr, int len, char value);
程序例:
#include ;
#include ;
#include ;
int main(void)
{
char *dest;
dest = calloc(21, sizeof(char));
setmem(dest, 20, 'c');
printf("%s\n", dest);
return 0;
}



函數名: setmode
功 能: 設置打開文件方式
用 法: int setmode(int handle, unsigned mode);
程序例:
#include ;
#include ;
#include ;
int main(void)
{
int result;
result = setmode(fileno(stdprn), O_TEXT);
if (result == -1)
perror("Mode not available\n");
else
printf("Mode successfully switched\n");
return 0;
}



函數名: setpalette
功 能: 改變調色板的顏色
用 法: void far setpalette(int index, int actural_color);
程序例:
#include ;
#include ;
#include ;
#include ;
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int color, maxcolor, ht;
int y = 10;
char msg[80];
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
maxcolor = getmaxcolor();
ht = 2 * textheight("W");
/* display the default colors */
for (color=1; color<=maxcolor; color++)
{
setcolor(color);
sprintf(msg, "Color: %d", color);
outtextxy(1, y, msg);
y += ht;
}
/* wait for a key */
getch();
/* black out the colors one by one */
for (color=1; color<=maxcolor; color++)
{
setpalette(color, BLACK);
getch();
}
/* clean up */
closegraph();
return 0;
}


函數名: setrgbpalette
功 能: 定義IBM8514圖形卡的顏色
用 法: void far setrgbpalette(int colornum, int red, int green, int blue);
程序例:
#include ;
#include ;
#include ;
#include ;
int main(void)
{
/* select a driver and mode that supports the use */
/* of the setrgbpalette function. */
int gdriver = VGA, gmode = VGAHI, errorcode;
struct palettetype pal;
int i, ht, y, xmax;
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
/* grab a copy of the palette */
getpalette(&pal);
/* create gray scale */
for (i=0; i /* display the gray scale */
ht = getmaxy() / 16;
xmax = getmaxx();
y = 0;
for (i=0; i {
setfillstyle(SOLID_FILL, i);
bar(0, y, xmax, y+ht);
y += ht;
}
/* clean up */
getch();
closegraph();
return 0;
}



函數名: settextjustify
功 能: 為圖形函數設置文本的對齊方式
用 法: void far settextjustify(int horiz, int vert);
程序例:
#include ;
#include ;
#include ;
#include ;
/* function prototype */
void xat(int x, int y);
/* horizontal text justification settings */
char *hjust[] = { "LEFT_TEXT",
"CENTER_TEXT",
"RIGHT_TEXT"
};
/* vertical text justification settings */
char *vjust[] = { "LEFT_TEXT",
"CENTER_TEXT",
"RIGHT_TEXT"
};
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int midx, midy, hj, vj;
char msg[80];
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
midx = getmaxx() / 2;
midy = getmaxy() / 2;
/* loop through text justifications */
for (hj=LEFT_TEXT; hj<=RIGHT_TEXT; hj++)
for (vj=LEFT_TEXT; vj<=RIGHT_TEXT; vj++)
{
cleardevice();
/* set the text justification */
settextjustify(hj, vj);
/* create a message string */
sprintf(msg, "%s %s", hjust[hj], vjust[vj]);
/* create cross hairs on the screen */
xat(midx, midy);
/* output the message */
outtextxy(midx, midy, msg);
getch();
}
/* clean up */
closegraph();
return 0;
}
/* draw an "x" at (x, y) */
void xat(int x, int y)
{
line(x-4, y, x+4, y);
line(x, y-4, x, y+4);
}


函數名: settextstyle
功 能: 為圖形輸出設置當前的文本屬性
用 法: void far settextstyle (int font, int direction, char size);
程序例:
#include ;
#include ;
#include ;
#include ;
/* the names of the text styles supported */
char *fname[] = { "DEFAULT font",
"TRIPLEX font",
"SMALL font",
"SANS SERIF font",
"GOTHIC font"
};
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int style, midx, midy;
int size = 1;
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
midx = getmaxx() / 2;
midy = getmaxy() / 2;
settextjustify(CENTER_TEXT, CENTER_TEXT);
/* loop through the available text styles */
for (style=DEFAULT_FONT; style<=GOTHIC_FONT; style++)
{
cleardevice();
if (style == TRIPLEX_FONT)
size = 4;
/* select the text style */
settextstyle(style, HORIZ_DIR, size);
/* output a message */
outtextxy(midx, midy, fname[style]);
getch();
}
/* clean up */
closegraph();
return 0;
}


函數名: settextstyle
功 能: 為圖形輸出設置當前的文本屬性
用 法: void far settextstyle (int font, int direction, char size);
程序例:
#include ;
#include ;
#include ;
#include ;
/* the names of the text styles supported */
char *fname[] = { "DEFAULT font",
"TRIPLEX font",
"SMALL font",
"SANS SERIF font",
"GOTHIC font"
};
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int style, midx, midy;
int size = 1;
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
midx = getmaxx() / 2;
midy = getmaxy() / 2;
settextjustify(CENTER_TEXT, CENTER_TEXT);
/* loop through the available text styles */
for (style=DEFAULT_FONT; style<=GOTHIC_FONT; style++)
{
cleardevice();
if (style == TRIPLEX_FONT)
size = 4;
/* select the text style */
settextstyle(style, HORIZ_DIR, size);
/* output a message */
outtextxy(midx, midy, fname[style]);
getch();
}
/* clean up */
closegraph();
return 0;
}


函數名: settime
功 能: 設置系統時間
用 法: void settime(struct time *timep);
程序例:
#include ;
#include ;
int main(void)
{
struct time t;
gettime(&t);
printf("The current minute is: %d\n", t.ti_min);
printf("The current hour is: %d\n", t.ti_hour);
printf("The current hundredth of a second is: %d\n", t.ti_hund);
printf("The current second is: %d\n", t.ti_sec);
/* Add one to the minutes struct element and then call settime */
t.ti_min++;
settime(&t);
return 0;
}


函數名: setusercharsize
功 能: 為矢量字體改變字符寬度和高度
用 法: void far setusercharsize(int multx, int dirx, int multy, int diry);
程序例:
#include ;
#include ;
#include ;
#include ;
int main(void)
{
/* request autodetection */
int gdriver = DETECT, gmode, errorcode;
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
/* select a text style */
settextstyle(TRIPLEX_FONT, HORIZ_DIR, 4);
/* move to the text starting position */
moveto(0, getmaxy() / 2);
/* output some normal text */
outtext("Norm ");
/* make the text 1/3 the normal width */
setusercharsize(1, 3, 1, 1);
outtext("Short ");
/* make the text 3 times normal width */
setusercharsize(3, 1, 1, 1);
outtext("Wide");
/* clean up */
getch();
closegraph();
return 0;
}

函數名: setvbuf
功 能: 把緩沖區與流相關
用 法: int setvbuf(FILE *stream, char *buf, int type, unsigned size);
程序例:
#include ;
int main(void)
{
FILE *input, *output;
char bufr[512];
input = fopen("file.in", "r+b");
output = fopen("file.out", "w");
/* set up input stream for minimal disk access,
using our own character buffer */
if (setvbuf(input, bufr, _IOFBF, 512) != 0)
printf("failed to set up buffer for input file\n");
else
printf("buffer set up for input file\n");
/* set up output stream for line buffering using space that
will be obtained through an indirect call to malloc */
if (setvbuf(output, NULL, _IOLBF, 132) != 0)
printf("failed to set up buffer for output file\n");
else
printf("buffer set up for output file\n");
/* perform file I/O here */
/* close files */
fclose(input);
fclose(output);
return 0;
}



函數名: setvect
功 能: 設置中斷矢量入口
用 法: void setvect(int intr_num, void interrupt(*isr)());
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 ;
#include ;
#include ;
#define INTR 0X1C /* The clock tick interrupt */
void interrupt ( *oldhandler)(void);
int count=0;
void interrupt handler(void)
{
/* increase the global counter */
count++;
/* 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;
}


函數名: setverify
功 能: 設置驗證狀態
用 法: void setverify(int value);
程序例:
#include ;
#include ;
#include ;
int main(void)
{
int verify_flag;
printf("Enter 0 to set verify flag off\n");
printf("Enter 1 to set verify flag on\n");
verify_flag = getch() - 0;
setverify(verify_flag);
if (getverify())
printf("DOS verify flag is on\n");
else
printf("DOS verify flag is off\n");
return 0;
}


函數名: setviewport
功 能: 為圖形輸出設置當前視口
用 法: void far setviewport(int left, int top, int right,
int bottom, int clipflag);
程序例:
#include ;
#include ;
#include ;
#include ;
#define CLIP_ON 1 /* activates clipping in viewport */
int main(void)
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
setcolor(getmaxcolor());
/* message in default full-screen viewport */
outtextxy(0, 0, "* <-- (0, 0) in default viewport");
/* create a smaller viewport */
setviewport(50, 50, getmaxx()-50, getmaxy()-50, CLIP_ON);
/* display some text */
outtextxy(0, 0, "* <-- (0, 0) in smaller viewport");
/* clean up */
getch();
closegraph();
return 0;
}


函數名: setvisualpage
功 能: 設置可見圖形頁號
用 法: void far setvisualpage(int pagenum);
程序例:
#include ;
#include ;
#include ;
#include ;
int main(void)
{
/* select a driver and mode that supports */
/* multiple pages. */
int gdriver = EGA, gmode = EGAHI, errorcode;
int x, y, ht;
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
x = getmaxx() / 2;
y = getmaxy() / 2;
ht = textheight("W");
/* select the off screen page for drawing */
setactivepage(1);
/* draw a line on page #1 */
line(0, 0, getmaxx(), getmaxy());
/* output a message on page #1 */
settextjustify(CENTER_TEXT, CENTER_TEXT);
outtextxy(x, y, "This is page #1:");
outtextxy(x, y+ht, "Press any key to halt:");
/* select drawing to page #0 */
setactivepage(0);
/* output a message on page #0 */
outtextxy(x, y, "This is page #0.");
outtextxy(x, y+ht, "Press any key to view page #1:");
getch();
/* select page #1 as the visible page */
setvisualpage(1);
/* clean up */
getch();
closegraph();
return 0;
}


函數名: setwritemode
功 能: 設置圖形方式下畫線的輸出模式
用 法: void far setwritemode(int mode);
程序例:
#include ;
#include ;
#include ;
#include ;
int main()
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int xmax, ymax;
/* initialize graphics and 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("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
xmax = getmaxx();
ymax = getmaxy();
/* select XOR drawing mode */
setwritemode(XOR_PUT);
/* draw a line */
line(0, 0, xmax, ymax);
getch();
/* erase the line by drawing over it */
line(0, 0, xmax, ymax);
getch();
/* select overwrite drawing mode */
setwritemode(COPY_PUT);
/* draw a line */
line(0, 0, xmax, ymax);
/* clean up */
getch();
closegraph();
return 0;
}


函數名: signal
功 能: 設置某一信號的對應動作
用 法: int signal(int sig, sigfun fname);
程序例:
/* This example installs a signal handler routine for SIGFPE,
catches an integer overflow condition, makes an adjustment
to AX register, and returns. This example program MAY cause
your computer to crash, and will produce runtime errors
depending on which memory model is used.
*/
#pragma inline
#include ;
#include ;
void Catcher(int sig, int type, int *reglist)
{
printf("Caught it!\n");
*(reglist + 8) = 3; /* make return AX = 3 */
}
int main(void)
{
signal(SIGFPE, Catcher);
asm mov ax,07FFFH /* AX = 32767 */
asm inc ax /* cause overflow */
asm into /* activate handler */
/* The handler set AX to 3 on return. If that hadn't happened,
there would have been another exception when the next 'into'
was executed after the 'dec' instruction. */
asm dec ax /* no overflow now */
asm into /* doesn't activate */
return 0;
}



函數名: sin
功 能: 正弦函數
用 法: double sin(double x);
程序例:
#include ;
#include ;
int main(void)
{
double result, x = 0.5;
result = sin(x);
printf("The sin() of %lf is %lf\n", x, result);
return 0;
}


函數名: sinh
功 能: 雙曲正弦函數
用 法: double sinh(double x);
程序例:
#include ;
#include ;
int main(void)
{
double result, x = 0.5;
result = sinh(x);
printf("The hyperbolic sin() of %lf is %lf\n", x, result);
return 0;
}



函數名: sleep
功 能: 執行掛起一段時間
用 法: unsigned sleep(unsigned seconds);
程序例:
#include ;
#include ;
int main(void)
{
int i;
for (i=1; i<5; i++)
{
printf("Sleeping for %d seconds\n", i);
sleep(i);
}
return 0;
}



函數名: sopen
功 能: 打開一共享文件
用 法: int sopen(char *pathname, int access, int shflag, int permiss);
程序例:
#include ;
#include ;
#include ;
#include ;
#include ;
#include ;
int main(void)
{
int handle;
int status;
handle = sopen("c:\\autoexec.bat", O_RDONLY, SH_DENYNO, S_IREAD);
if (!handle)
{
printf("sopen failed\n");
exit(1);
}
status = access("c:\\autoexec.bat", 6);
if (status == 0)
printf("read/write access allowed\n");
else
printf("read/write access not allowed\n");
close(handle);
return 0;
}
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