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Full Discussion: Multiplying 2D arrays using fork()
Top Forums Programming Multiplying 2D arrays using fork() Post 302611489 by agama on Friday 23rd of March 2012 12:15:45 AM
Old 03-23-2012
Great progress!

You need to correct a few things if you haven't.

First, the warning about %s in conjunction with strerror() is because you haven't included string.h. The strerror() function returns a pointer to a string, and if you don't include string.h the compiler assumes that it returns int, and thus issues the warning about the mismatch with %s. Include string.h and change the %d to a %s. It has nothing to do with the type of errno.

You also should include sys/types.h and sys/wait.h.

Your initialisation of a, b and c is missing curly braces. To be correct, you need something like this for a and b:
Code:
int a[2][3] = { {1,2,3},
                   {4,5,6} };

For c you need
Code:
int c[2][4] = { {0}, {0} };

Those are all to correct compiler warnings. The real problem is in your writing from the child. You are converting each value to string and placing it in str with a terminating NULL character. That is correct. However, you are writing the entire buffer, including the characters past the NULL to the parent. You need to write just the values, and the associated trailing blank, to the parent. To do this you need to capture the length of the string created by sprintf() and use that as the number of characters to write to the pipe. For completeness, I would also write a final NULL to the pipe after all of the values. Something like the code segment below:

Code:
                    len = sprintf( str, "%d ", c[i][j] );   // length of value+blank into len
                    w = write( pipefd[1], str, len  );     // write only the value and blank
                    if( w != len )                         // check the number written, not the size of str
                        printf("\nWrite error");        // maybe exit too?
            }
            *str = 0;                     // write a final NULL to terminate the string
            write( pipefd[1], str, 1 );
            exit(0);

This User Gave Thanks to agama For This Post:
giampoul
 

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LEARN ABOUT SUNOS

sasl_utf8verify

sasl_utf8verify(3SASL)			      Simple Authentication Security Layer Library Functions			    sasl_utf8verify(3SASL)

NAME

       sasl_utf8verify - encode base64 string

SYNOPSIS

       cc [ flag ... ] file ... -lsasl	 [ library ... ]
       #include <sasl/saslutil.h>

       int sasl_utf8verify(const char *str, unsigned len);

DESCRIPTION

       Use  the sasl_utf8verify() interface to verify that a string is valid UTF-8 and does not contain NULL, a carriage return, or a linefeed. If
       len ==0, strlen(str) will be used.

PARAMETERS

       str	A string

       len	The length of the string

RETURN VALUES

       sasl_utf8verify() returns an integer that corresponds to a SASL error code.

ERRORS

       SASL_OK	       The call to sasl_utf8verify() was successful.

       SASL_BADPROT    There was invalid UTF-8, or an error was found.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWlibsasl		   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       attributes(5)

SunOS 5.10							    1 Oct 2003						    sasl_utf8verify(3SASL)
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