how to save 2 shorts and a bunch of unsigneds in a char* array?

Bats

I'm writing an XSUB to glue an existing C module to my perl code, but I'm kind of new to C.
I want to save 2 shorts and n unsigneds in a char * array (so I can return the array to the perl module and store it in a mysql table right away). I have looked into memcpy, but it doesn't seem to do what I want. This is what I am trying right now:

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 short some_func() { ... }

unsigned some_other_func() { ... }

int n = 128;
 
char * return_func() {

  char * result = malloc( sizeof( short ) * 2 + sizeof( unsigned ) * n );

  int pos = 0;

  short s = some_func();

  memcpy( &result[pos], &s, sizeof(short) );

  pos += sizeof(short);

  s = some_func();

  memcpy( &result[pos], &s, sizeof(short) );

  pos += sizeof(short);
 
  int i;

  for( i=0; i<n; i++ ) {

    unsigned u = some_other_func();

    memcpy( &result[pos], &u, sizeof( unsigned ) );

    pos += sizeof( unsigned );

  }
 
  return result;

}

Is there a better way to do this, without memcpy?
Or should i call memcpy in a different way?
Google couldn't help me out.

Thanks in advance.

JosAH

Quote:

Originally Posted by Bats

I'm writing an XSUB to glue an existing C module to my perl code, but I'm kind of new to C.
I want to save 2 shorts and n unsigneds in a char * array (so I can return the array to the perl module and store it in a mysql table right away). I have looked into memcpy, but it doesn't seem to do what I want. This is what I am trying right now

What doesn't it do what you want? Or what does it do that you don't want? Your program fragment seems ok to me.

kind regards,

Jos

Bats

if I add this before the return:

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   int len = strlen(result);

  printf( "len: %d\n", len );

I see

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len: 2

newb16

What does XSUB expect in this string to interpret is an array of numbers?

JosAH

Quote:

Originally Posted by Bats

if I add this before the return:

Expand|Select|Wrap|Line Numbers

   int len = strlen(result);

  printf( "len: %d\n", len );

I see

Expand|Select|Wrap|Line Numbers

len: 2

The result is not a string because you have copied two shorts to the start of the buffer; if one byte of those shorts contains a nul byte it will be considered the end of the 'string'.

kind regards,

Jos

how to save 2 shorts and a bunch of unsigneds in a char* array?

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re: how to save 2 shorts and a bunch of unsigneds in a char* array?

re: how to save 2 shorts and a bunch of unsigneds in a char* array?

re: how to save 2 shorts and a bunch of unsigneds in a char* array?

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