Rockwell-automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User M Manual de usuario descargar pdf (Pagina 59)

Chapter 4

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4-7

Example Program to Access RAM Disk

Refer to the following C program (CAT.C) as an example of accessing

the control-coprocessor RAM disk. Note the use of standard C library

functions—e.g.,

fopen(), getc(), and fclose()—to access RAM-

disk files.

You create the file, compile it, and send it to OS-9 as a binary file.

Then, you run the C program on OS-9.

/***** cat.c ::: copy from files to standard out *****

* This program is used as an example so you can learn to use the

* Standard Library functions for processing characters from an

* input file and writing characters on the standard output,

* and so you can use a command in a “pipeline” with redirection

* modifiers (’<’ and ’>’). Try doing a:

* cat file1 file2 file3 > outfile

* type of operation to see how “cat” can merge files...

* “What goes around, comes around.”

/* First, includes and defines... */

#include <stdio.h> /* needed for ’getc()’ and ’putchar()’ */

#include <errno.h> /* needed for ’errno’ to work */

/* then the function and parameter declarations... */

main ( argc, argv )

int argc;

char **argv;

/* then the body of executable function statements... */

{

/* private variable declarations */

FILE *infil; /* file to copy to standard output */

int c, /* character (or EOF) gotten from input file */

i; /* which command line argument is being processed */

* This command has no option switches. It simply copies the

* input file(s) character by character to standard output.

* If only the command itself is specified, it does nothing.

* Probably better tell the user such...!

if ( argc == 1 ) /* no file names on command line */

{

fprintf ( stderr, “No files on command line. Exiting.\n” );

exit ( 0 );

}

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Rockwell-automation 1771-DMC_DMC1_DMC4_DXPS Control Coprocessor User M Manual de usuario Pagina 59