getting a function to return a char array

**Dave_Sinkula** · 02-08-2005

I think it has to do with how gcc handles functions that return structures.

-fpcc-struct-return
Return “short” struct and union values in memory like longer ones, rather than in registers. This convention is less efficient, but it has the advantage of allowing intercallability between GCC-compiled files and files compiled with other compilers, particularly the Portable C Compiler (pcc).

The precise convention for returning structures in memory depends on the target configuration macros.

Short structures and unions are those whose size and alignment match that of some integer type.

Warning: code compiled with the -fpcc-struct-return switch is not binary compatible with code compiled with the -freg-struct-return switch. Use it to conform to a non-default application binary interface.

http://gcc.gnu.org/onlinedocs/gccint...te-Return.html

**variable** · 02-09-2005

could i also do something like this?

Code:

#include <stdio.h> 

char testmain[5];

int postchar( void )
{
    testmain[0]='a';
    
       printf("%s",testmain);
       return;
}

int main( void )
{
    postchar();
  printf("%s",testmain);
  
  getch();
  
  return 0;
}

++ does anyone have a link to what the -> does , i cant search it on google because it wont let me.

thanks

**anonytmouse** · 02-09-2005

http://vergil.chemistry.gatech.edu/r...l/structs.html

**variable** · 02-10-2005

thanks for the link.

is the code i posted ok? i know it works, but sometimes just because it works, it isnt right.

**anonytmouse** · 02-10-2005

Yes, your code is fine. All global variables are zeroed out at startup. So at startup testmain looks like:

Code:

'\0' '\0' '\0' '\0' '\0'

Once you run:

Code:

testmain[0] = 'a';

it will look like:

Code:

'a' '\0' '\0' '\0' '\0'

This is a valid string so you can safely prinit it out. However, the use of globals to pass data from one function to another is often frowned upon. It is usually better to use function arguments.

**variable** · 02-10-2005

ah, ok thanks for the help

--variable

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