cppreference的std::errc: std::errc - cppreference.com
对应定义(come from: 2022\Community\VC\Tools\MSVC\14.33.31629\include\xerrc.h)
cpp
enum class errc { // names for generic error codes
address_family_not_supported = 102, // EAFNOSUPPORT
address_in_use = 100, // EADDRINUSE
address_not_available = 101, // EADDRNOTAVAIL
already_connected = 113, // EISCONN
argument_list_too_long = 7, // E2BIG
argument_out_of_domain = 33, // EDOM
bad_address = 14, // EFAULT
bad_file_descriptor = 9, // EBADF
bad_message = 104, // EBADMSG
broken_pipe = 32, // EPIPE
connection_aborted = 106, // ECONNABORTED
connection_already_in_progress = 103, // EALREADY
connection_refused = 107, // ECONNREFUSED
connection_reset = 108, // ECONNRESET
cross_device_link = 18, // EXDEV
destination_address_required = 109, // EDESTADDRREQ
device_or_resource_busy = 16, // EBUSY
directory_not_empty = 41, // ENOTEMPTY
executable_format_error = 8, // ENOEXEC
file_exists = 17, // EEXIST
file_too_large = 27, // EFBIG
filename_too_long = 38, // ENAMETOOLONG
function_not_supported = 40, // ENOSYS
host_unreachable = 110, // EHOSTUNREACH
identifier_removed = 111, // EIDRM
illegal_byte_sequence = 42, // EILSEQ
inappropriate_io_control_operation = 25, // ENOTTY
interrupted = 4, // EINTR
invalid_argument = 22, // EINVAL
invalid_seek = 29, // ESPIPE
io_error = 5, // EIO
is_a_directory = 21, // EISDIR
message_size = 115, // EMSGSIZE
network_down = 116, // ENETDOWN
network_reset = 117, // ENETRESET
network_unreachable = 118, // ENETUNREACH
no_buffer_space = 119, // ENOBUFS
no_child_process = 10, // ECHILD
no_link = 121, // ENOLINK
no_lock_available = 39, // ENOLCK
no_message_available = 120, // ENODATA
no_message = 122, // ENOMSG
no_protocol_option = 123, // ENOPROTOOPT
no_space_on_device = 28, // ENOSPC
no_stream_resources = 124, // ENOSR
no_such_device_or_address = 6, // ENXIO
no_such_device = 19, // ENODEV
no_such_file_or_directory = 2, // ENOENT
no_such_process = 3, // ESRCH
not_a_directory = 20, // ENOTDIR
not_a_socket = 128, // ENOTSOCK
not_a_stream = 125, // ENOSTR
not_connected = 126, // ENOTCONN
not_enough_memory = 12, // ENOMEM
not_supported = 129, // ENOTSUP
operation_canceled = 105, // ECANCELED
operation_in_progress = 112, // EINPROGRESS
operation_not_permitted = 1, // EPERM
operation_not_supported = 130, // EOPNOTSUPP
operation_would_block = 140, // EWOULDBLOCK
owner_dead = 133, // EOWNERDEAD
permission_denied = 13, // EACCES
protocol_error = 134, // EPROTO
protocol_not_supported = 135, // EPROTONOSUPPORT
read_only_file_system = 30, // EROFS
resource_deadlock_would_occur = 36, // EDEADLK
resource_unavailable_try_again = 11, // EAGAIN
result_out_of_range = 34, // ERANGE
state_not_recoverable = 127, // ENOTRECOVERABLE
stream_timeout = 137, // ETIME
text_file_busy = 139, // ETXTBSY
timed_out = 138, // ETIMEDOUT
too_many_files_open_in_system = 23, // ENFILE
too_many_files_open = 24, // EMFILE
too_many_links = 31, // EMLINK
too_many_symbolic_link_levels = 114, // ELOOP
value_too_large = 132, // EOVERFLOW
wrong_protocol_type = 136 // EPROTOTYPE
};示例代码:
cpp
void print_error(const std::string& details, std::error_code error_code)
{
std::string value_name;
if (error_code == std::errc::invalid_argument)
value_name = "std::errc::invalid_argument";
if (error_code == std::errc::no_such_file_or_directory)
value_name = "std::errc::no_such_file_or_directory";
if (error_code == std::errc::is_a_directory)
value_name = "std::errc::is_a_directory";
if (error_code == std::errc::permission_denied)
value_name = "std::errc::permission_denied";
std::cout << details << ":\n "
<< std::quoted(error_code.message())
<< " (" << value_name << "), " << error_code
<< " \n";
}
void print_errno(const std::string& details, int errno_value = errno)
{
print_error(details, std::make_error_code(std::errc(errno_value)));
}
void testMain()
{
// Detaching a not-a-thread
try
{
std::thread().detach();
}
catch (const std::system_error& e)
{
print_error("Error detaching empty thread", e.code());
}
// Opening nonexistent file
{
std::ifstream nofile("nonexistent-file");
if (!nofile.is_open())
{
print_errno("Error opening nonexistent file for reading");
}
}
// Reading from directory as a file
{
std::filesystem::create_directory("testDir");
std::ifstream dir_stream("testDir");
[[maybe_unused]] char c = dir_stream.get();
if (!dir_stream.good())
{
print_errno("Error reading data from directory");
}
}
// Open readonly file for writing
{
{
std::fstream new_file("readonly-file", std::ios::out);
}
std::filesystem::permissions("readonly-file", std::filesystem::perms::owner_read);
std::fstream write_readonly("readonly-file", std::ios::out);
if (!write_readonly.is_open())
{
print_errno("Error opening readonly file for writing");
}
}
}运行程序之后的输出:
cpp
Error detaching empty thread:
"invalid argument" (std::errc::invalid_argument), generic:22
Error opening nonexistent file for reading:
"no such file or directory" (std::errc::no_such_file_or_directory), generic:2
Error reading data from directory:
"permission denied" (std::errc::permission_denied), generic:13
Error opening readonly file for writing:
"permission denied" (std::errc::permission_denied), generic:13