Improve doc about length of strings written
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index fb86d4c..c0abc52 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -228,8 +228,8 @@
* \param prefix A line prefix
* \param crt The X509 certificate to represent
*
- * \return The amount of data written to the buffer, or -1 in
- * case of an error.
+ * \return The length of the string written (not including the
+ * terminated nul byte), or a negative error code.
*/
int mbedtls_x509_crt_info( char *buf, size_t size, const char *prefix,
const mbedtls_x509_crt *crt );
@@ -243,8 +243,8 @@
* \param prefix A line prefix
* \param flags Verification flags created by mbedtls_x509_crt_verify()
*
- * \return The amount of data written to the buffer, or -1 in
- * case of an error.
+ * \return The length of the string written (not including the
+ * terminated nul byte), or a negative error code.
*/
int mbedtls_x509_crt_verify_info( char *buf, size_t size, const char *prefix,
uint32_t flags );