[PATCH] doc: Improve example gcry_control usage.

[Florian Forster]

* doc/gcrypt.texi: Change example code to check return value of
  gcry_control(GCRYCTL_INIT_SECMEM, …).
---
 doc/gcrypt.texi | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/doc/gcrypt.texi b/doc/gcrypt.texi
index c2c39ad..9486400 100644
--- a/doc/gcrypt.texi
+++ b/doc/gcrypt.texi
@@ -424,7 +424,10 @@ and freed memory, you need to initialize Libgcrypt this way:
 
   /* Allocate a pool of 16k secure memory.  This make the secure memory
      available and also drops privileges where needed.  */
-  gcry_control (GCRYCTL_INIT_SECMEM, 16384, 0);
+  if (gcry_control (GCRYCTL_INIT_SECMEM, 16384, 0)) {
+    fputs ("initializing secure memory failed\n", stderr);
+    exit (EXIT_FAILURE);
+  }
 
 @anchor{sample-use-resume-secmem}
   /* It is now okay to let Libgcrypt complain when there was/is
@@ -687,7 +690,8 @@ enabling the use of secure memory.  It also drops all extra privileges
 the process has (i.e. if it is run as setuid (root)).  If the argument
 @var{nbytes} is 0, secure memory will be disabled.  The minimum amount
 of secure memory allocated is currently 16384 bytes; you may thus use a
-value of 1 to request that default size.
+value of 1 to request that default size.  Returns zero on success and
+non-zero on failure.
 
 @item GCRYCTL_TERM_SECMEM; Arguments: none
 This command zeroises the secure memory and destroys the handler.  The
-- 
2.8.0.rc3.226.g39d4020