gpg_err_code_from_errno usage

Werner Koch wk at
Sat Mar 11 15:49:02 CET 2006

On Sat, 11 Mar 2006 11:52:26 +0100, Nikos Mavrogiannopoulos said:

> On Sat 11 Mar 2006 10:45, Marcus Brinkmann wrote:
>> > But how can you be sure that calloc() (or in that case gcry_calloc)
>> > will set the errno? calloc is a library call which may or may not
>> > use a system call. Even if it works on some systems, this is a very
>> > non-portable construction, which will result in no error checking
>> > in systems that do not set errno.
>> It's not in ISO C, but in POSIX.  Single Unix v3 has:

> Maybe but this doesn't change my argument. It is less portable than
> the ISO/ANSI C  behavior. Given that libgcrypt is already ported to 
> non-UNIX systems as well[0], I would consider this a bug.

To protect against ill behaving implementaions we even use some
failsafe code in the internal malloc code:

gcry_malloc (size_t n, unsigned int flags, void **mem)
 /* Call standard malloc or user registered function.  */
  if (!m)
      /* Make sure that ERRNO has been set in case a user supplied
         memory handler didn't it correctly. */
      if (!errno)
        errno = ENOMEM;
      err = gpg_err_code_from_errno (errno);
    *mem = m;

  return err;



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