Prefer eprintln over println for error messages

5 files changed, 52 insertions, 52 deletions

diff --git a/src/auth.rs b/src/auth.rs
index 18b6572..8978f32 100644
--- a/src/auth.rs
+++ b/src/auth.rs
@@ -49,7 +49,7 @@ pub trait Authenticate {
     ///         user.device()
     ///     },
     ///     Err((device, err)) => {
-    ///         println!("Could not authenticate as user: {}", err);
+    ///         eprintln!("Could not authenticate as user: {}", err);
     ///         device
     ///     },
     /// };
@@ -95,7 +95,7 @@ pub trait Authenticate {
     ///         admin.device()
     ///     },
     ///     Err((device, err)) => {
-    ///         println!("Could not authenticate as admin: {}", err);
+    ///         eprintln!("Could not authenticate as admin: {}", err);
     ///         device
     ///     },
     /// };
@@ -282,7 +282,7 @@ impl<T: Device> Admin<T> {
     ///         admin.write_config(config);
     ///         ()
     ///     },
-    ///     Err((_, err)) => println!("Could not authenticate as admin: {}", err),
+    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
     /// };
     /// #     Ok(())
     /// # }
diff --git a/src/device.rs b/src/device.rs
index 2fac4f2..d199d9a 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -78,7 +78,7 @@ impl fmt::Display for VolumeMode {
 ///         user.device()
 ///     },
 ///     Err((device, err)) => {
-///         println!("Could not authenticate as user: {}", err);
+///         eprintln!("Could not authenticate as user: {}", err);
 ///         device
 ///     },
 /// };
@@ -142,7 +142,7 @@ pub enum DeviceWrapper {
 ///         user.device()
 ///     },
 ///     Err((device, err)) => {
-///         println!("Could not authenticate as user: {}", err);
+///         eprintln!("Could not authenticate as user: {}", err);
 ///         device
 ///     },
 /// };
@@ -188,7 +188,7 @@ pub struct Pro {
 ///         user.device()
 ///     },
 ///     Err((device, err)) => {
-///         println!("Could not authenticate as user: {}", err);
+///         eprintln!("Could not authenticate as user: {}", err);
 ///         device
 ///     },
 /// };
@@ -325,7 +325,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.get_serial_number() {
     ///     Ok(number) => println!("serial no: {}", number),
-    ///     Err(err) => println!("Could not get serial number: {}", err),
+    ///     Err(err) => eprintln!("Could not get serial number: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -347,7 +347,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.get_user_retry_count() {
     ///     Ok(count) => println!("{} remaining authentication attempts (user)", count),
-    ///     Err(err) => println!("Could not get user retry count: {}", err),
+    ///     Err(err) => eprintln!("Could not get user retry count: {}", err),
     /// }
     /// #     Ok(())
     /// # }
@@ -370,7 +370,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let count = device.get_admin_retry_count();
     /// match device.get_admin_retry_count() {
     ///     Ok(count) => println!("{} remaining authentication attempts (admin)", count),
-    ///     Err(err) => println!("Could not get admin retry count: {}", err),
+    ///     Err(err) => eprintln!("Could not get admin retry count: {}", err),
     /// }
     /// #     Ok(())
     /// # }
@@ -391,7 +391,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.get_firmware_version() {
     ///     Ok(version) => println!("Firmware version: {}", version),
-    ///     Err(err) => println!("Could not access firmware version: {}", err),
+    ///     Err(err) => eprintln!("Could not access firmware version: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -455,7 +455,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.change_admin_pin("12345678", "12345679") {
     ///     Ok(()) => println!("Updated admin PIN."),
-    ///     Err(err) => println!("Failed to update admin PIN: {}", err),
+    ///     Err(err) => eprintln!("Failed to update admin PIN: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -488,7 +488,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.change_user_pin("123456", "123457") {
     ///     Ok(()) => println!("Updated admin PIN."),
-    ///     Err(err) => println!("Failed to update admin PIN: {}", err),
+    ///     Err(err) => eprintln!("Failed to update admin PIN: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -521,7 +521,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.unlock_user_pin("12345678", "123456") {
     ///     Ok(()) => println!("Unlocked user PIN."),
-    ///     Err(err) => println!("Failed to unlock user PIN: {}", err),
+    ///     Err(err) => eprintln!("Failed to unlock user PIN: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -555,7 +555,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.lock() {
     ///     Ok(()) => println!("Locked the Nitrokey device."),
-    ///     Err(err) => println!("Could not lock the Nitrokey device: {}", err),
+    ///     Err(err) => eprintln!("Could not lock the Nitrokey device: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -586,7 +586,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.factory_reset("12345678") {
     ///     Ok(()) => println!("Performed a factory reset."),
-    ///     Err(err) => println!("Could not perform a factory reset: {}", err),
+    ///     Err(err) => eprintln!("Could not perform a factory reset: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -620,7 +620,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// let device = nitrokey::connect()?;
     /// match device.build_aes_key("12345678") {
     ///     Ok(()) => println!("New AES keys have been built."),
-    ///     Err(err) => println!("Could not build new AES keys: {}", err),
+    ///     Err(err) => eprintln!("Could not build new AES keys: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -649,7 +649,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
 ///
 /// match nitrokey::connect() {
 ///     Ok(device) => do_something(device),
-///     Err(err) => println!("Could not connect to a Nitrokey: {}", err),
+///     Err(err) => eprintln!("Could not connect to a Nitrokey: {}", err),
 /// }
 /// ```
 ///
@@ -681,7 +681,7 @@ pub fn connect() -> Result<DeviceWrapper, Error> {
 ///
 /// match nitrokey::connect_model(Model::Pro) {
 ///     Ok(device) => do_something(device),
-///     Err(err) => println!("Could not connect to a Nitrokey Pro: {}", err),
+///     Err(err) => eprintln!("Could not connect to a Nitrokey Pro: {}", err),
 /// }
 /// ```
 ///
@@ -785,7 +785,7 @@ impl Pro {
     ///
     /// match nitrokey::Pro::connect() {
     ///     Ok(device) => use_pro(device),
-    ///     Err(err) => println!("Could not connect to the Nitrokey Pro: {}", err),
+    ///     Err(err) => eprintln!("Could not connect to the Nitrokey Pro: {}", err),
     /// }
     /// ```
     ///
@@ -838,7 +838,7 @@ impl Storage {
     ///
     /// match nitrokey::Storage::connect() {
     ///     Ok(device) => use_storage(device),
-    ///     Err(err) => println!("Could not connect to the Nitrokey Storage: {}", err),
+    ///     Err(err) => eprintln!("Could not connect to the Nitrokey Storage: {}", err),
     /// }
     /// ```
     ///
@@ -878,7 +878,7 @@ impl Storage {
     /// let device = nitrokey::Storage::connect()?;
     /// match device.change_update_pin("12345678", "87654321") {
     ///     Ok(()) => println!("Updated update PIN."),
-    ///     Err(err) => println!("Failed to update update PIN: {}", err),
+    ///     Err(err) => eprintln!("Failed to update update PIN: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -915,7 +915,7 @@ impl Storage {
     /// let device = nitrokey::Storage::connect()?;
     /// match device.enable_firmware_update("12345678") {
     ///     Ok(()) => println!("Nitrokey entered update mode."),
-    ///     Err(err) => println!("Could not enter update mode: {}", err),
+    ///     Err(err) => eprintln!("Could not enter update mode: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -949,7 +949,7 @@ impl Storage {
     /// let device = nitrokey::Storage::connect()?;
     /// match device.enable_encrypted_volume("123456") {
     ///     Ok(()) => println!("Enabled the encrypted volume."),
-    ///     Err(err) => println!("Could not enable the encrypted volume: {}", err),
+    ///     Err(err) => eprintln!("Could not enable the encrypted volume: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -983,11 +983,11 @@ impl Storage {
     ///         match device.disable_encrypted_volume() {
     ///             Ok(()) => println!("Disabled the encrypted volume."),
     ///             Err(err) => {
-    ///                 println!("Could not disable the encrypted volume: {}", err);
+    ///                 eprintln!("Could not disable the encrypted volume: {}", err);
     ///             },
     ///         };
     ///     },
-    ///     Err(err) => println!("Could not enable the encrypted volume: {}", err),
+    ///     Err(err) => eprintln!("Could not enable the encrypted volume: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -1025,7 +1025,7 @@ impl Storage {
     /// device.enable_encrypted_volume("123445")?;
     /// match device.enable_hidden_volume("hidden-pw") {
     ///     Ok(()) => println!("Enabled a hidden volume."),
-    ///     Err(err) => println!("Could not enable the hidden volume: {}", err),
+    ///     Err(err) => eprintln!("Could not enable the hidden volume: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -1063,11 +1063,11 @@ impl Storage {
     ///         match device.disable_hidden_volume() {
     ///             Ok(()) => println!("Disabled the hidden volume."),
     ///             Err(err) => {
-    ///                 println!("Could not disable the hidden volume: {}", err);
+    ///                 eprintln!("Could not disable the hidden volume: {}", err);
     ///             },
     ///         };
     ///     },
-    ///     Err(err) => println!("Could not enable the hidden volume: {}", err),
+    ///     Err(err) => eprintln!("Could not enable the hidden volume: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -1144,7 +1144,7 @@ impl Storage {
     /// let device = nitrokey::Storage::connect()?;
     /// match device.set_unencrypted_volume_mode("123456", VolumeMode::ReadWrite) {
     ///     Ok(()) => println!("Set the unencrypted volume to read-write mode."),
-    ///     Err(err) => println!("Could not set the unencrypted volume to read-write mode: {}", err),
+    ///     Err(err) => eprintln!("Could not set the unencrypted volume to read-write mode: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -1184,7 +1184,7 @@ impl Storage {
     ///     Ok(status) => {
     ///         println!("SD card ID: {:#x}", status.serial_number_sd_card);
     ///     },
-    ///     Err(err) => println!("Could not get Storage status: {}", err),
+    ///     Err(err) => eprintln!("Could not get Storage status: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -1228,7 +1228,7 @@ impl Storage {
     ///         println!("SD card ID:   {:#x}", data.sd_card.serial_number);
     ///         println!("SD card size: {} GB", data.sd_card.size);
     ///     },
-    ///     Err(err) => println!("Could not get Storage production info: {}", err),
+    ///     Err(err) => eprintln!("Could not get Storage production info: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -1273,7 +1273,7 @@ impl Storage {
     /// let device = nitrokey::Storage::connect()?;
     /// match device.clear_new_sd_card_warning("12345678") {
     ///     Ok(()) => println!("Cleared the new SD card warning."),
-    ///     Err(err) => println!("Could not set the clear the new SD card warning: {}", err),
+    ///     Err(err) => eprintln!("Could not set the clear the new SD card warning: {}", err),
     /// };
     /// #     Ok(())
     /// # }
diff --git a/src/lib.rs b/src/lib.rs
index f2d524e..f7da8e1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -50,10 +50,10 @@
 //!     Ok(admin) => {
 //!         match admin.write_hotp_slot(slot_data, 0) {
 //!             Ok(()) => println!("Successfully wrote slot."),
-//!             Err(err) => println!("Could not write slot: {}", err),
+//!             Err(err) => eprintln!("Could not write slot: {}", err),
 //!         }
 //!     },
-//!     Err((_, err)) => println!("Could not authenticate as admin: {}", err),
+//!     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
 //! }
 //! #     Ok(())
 //! # }
@@ -69,7 +69,7 @@
 //! let device = nitrokey::connect()?;
 //! match device.get_hotp_code(1) {
 //!     Ok(code) => println!("Generated HOTP code: {}", code),
-//!     Err(err) => println!("Could not generate HOTP code: {}", err),
+//!     Err(err) => eprintln!("Could not generate HOTP code: {}", err),
 //! }
 //! #     Ok(())
 //! # }
diff --git a/src/otp.rs b/src/otp.rs
index 6e0379b..abaff66 100644
--- a/src/otp.rs
+++ b/src/otp.rs
@@ -41,10 +41,10 @@ pub trait ConfigureOtp {
     ///     Ok(admin) => {
     ///         match admin.write_hotp_slot(slot_data, 0) {
     ///             Ok(()) => println!("Successfully wrote slot."),
-    ///             Err(err) => println!("Could not write slot: {}", err),
+    ///             Err(err) => eprintln!("Could not write slot: {}", err),
     ///         }
     ///     },
-    ///     Err((_, err)) => println!("Could not authenticate as admin: {}", err),
+    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
     /// }
     /// #     Ok(())
     /// # }
@@ -77,10 +77,10 @@ pub trait ConfigureOtp {
     ///     Ok(admin) => {
     ///         match admin.write_totp_slot(slot_data, 30) {
     ///             Ok(()) => println!("Successfully wrote slot."),
-    ///             Err(err) => println!("Could not write slot: {}", err),
+    ///             Err(err) => eprintln!("Could not write slot: {}", err),
     ///         }
     ///     },
-    ///     Err((_, err)) => println!("Could not authenticate as admin: {}", err),
+    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
     /// }
     /// #     Ok(())
     /// # }
@@ -109,10 +109,10 @@ pub trait ConfigureOtp {
     ///     Ok(admin) => {
     ///         match admin.erase_hotp_slot(1) {
     ///             Ok(()) => println!("Successfully erased slot."),
-    ///             Err(err) => println!("Could not erase slot: {}", err),
+    ///             Err(err) => eprintln!("Could not erase slot: {}", err),
     ///         }
     ///     },
-    ///     Err((_, err)) => println!("Could not authenticate as admin: {}", err),
+    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
     /// }
     /// #     Ok(())
     /// # }
@@ -139,10 +139,10 @@ pub trait ConfigureOtp {
     ///     Ok(admin) => {
     ///         match admin.erase_totp_slot(1) {
     ///             Ok(()) => println!("Successfully erased slot."),
-    ///             Err(err) => println!("Could not erase slot: {}", err),
+    ///             Err(err) => eprintln!("Could not erase slot: {}", err),
     ///         }
     ///     },
-    ///     Err((_, err)) => println!("Could not authenticate as admin: {}", err),
+    ///     Err((_, err)) => eprintln!("Could not authenticate as admin: {}", err),
     /// }
     /// #     Ok(())
     /// # }
@@ -175,7 +175,7 @@ pub trait GenerateOtp {
     /// let time = time::SystemTime::now().duration_since(time::UNIX_EPOCH);
     /// match time {
     ///     Ok(time) => device.set_time(time.as_secs(), false)?,
-    ///     Err(_) => println!("The system time is before the Unix epoch!"),
+    ///     Err(_) => eprintln!("The system time is before the Unix epoch!"),
     /// }
     /// #     Ok(())
     /// # }
@@ -212,8 +212,8 @@ pub trait GenerateOtp {
     /// let device = nitrokey::connect()?;
     /// match device.get_hotp_slot_name(1) {
     ///     Ok(name) => println!("HOTP slot 1: {}", name),
-    ///     Err(Error::CommandError(CommandError::SlotNotProgrammed)) => println!("HOTP slot 1 not programmed"),
-    ///     Err(err) => println!("Could not get slot name: {}", err),
+    ///     Err(Error::CommandError(CommandError::SlotNotProgrammed)) => eprintln!("HOTP slot 1 not programmed"),
+    ///     Err(err) => eprintln!("Could not get slot name: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -241,8 +241,8 @@ pub trait GenerateOtp {
     /// let device = nitrokey::connect()?;
     /// match device.get_totp_slot_name(1) {
     ///     Ok(name) => println!("TOTP slot 1: {}", name),
-    ///     Err(Error::CommandError(CommandError::SlotNotProgrammed)) => println!("TOTP slot 1 not programmed"),
-    ///     Err(err) => println!("Could not get slot name: {}", err),
+    ///     Err(Error::CommandError(CommandError::SlotNotProgrammed)) => eprintln!("TOTP slot 1 not programmed"),
+    ///     Err(err) => eprintln!("Could not get slot name: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -313,7 +313,7 @@ pub trait GenerateOtp {
     ///         let code = device.get_totp_code(1)?;
     ///         println!("Generated TOTP code on slot 1: {}", code);
     ///     },
-    ///     Err(_) => println!("Timestamps before 1970-01-01 are not supported!"),
+    ///     Err(_) => eprintln!("Timestamps before 1970-01-01 are not supported!"),
     /// }
     /// #     Ok(())
     /// # }
diff --git a/src/pws.rs b/src/pws.rs
index fcf057b..1e27935 100644
--- a/src/pws.rs
+++ b/src/pws.rs
@@ -103,7 +103,7 @@ pub trait GetPasswordSafe {
     ///         use_password_safe(&pws);
     ///         device.lock()?;
     ///     },
-    ///     Err(err) => println!("Could not open the password safe: {}", err),
+    ///     Err(err) => eprintln!("Could not open the password safe: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -201,7 +201,7 @@ impl<'a> PasswordSafe<'a> {
     ///         let password = pws.get_slot_login(0)?;
     ///         println!("Credentials for {}: login {}, password {}", name, login, password);
     ///     },
-    ///     Err(err) => println!("Could not open the password safe: {}", err),
+    ///     Err(err) => eprintln!("Could not open the password safe: {}", err),
     /// };
     /// #     Ok(())
     /// # }
@@ -344,7 +344,7 @@ impl<'a> PasswordSafe<'a> {
     /// let pws = device.get_password_safe("123456")?;
     /// match pws.erase_slot(0) {
     ///     Ok(()) => println!("Erased slot 0."),
-    ///     Err(err) => println!("Could not erase slot 0: {}", err),
+    ///     Err(err) => eprintln!("Could not erase slot 0: {}", err),
     /// };
     /// #     Ok(())
     /// # }