C Error Number
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In C programming language, there is no direct support for error handling. You have to detect the failure and handle the error. In C programming language, return values represents success or failure. Inside a C program, when a function fails, you should handle c errno the errors accordingly, or at least record the errors in a log file. When you are running print error number in c some program on Linux environment, you might notice that it gives some error number. For example, "Error no is : 17", which doesn't really
C Errno Example
say much. You really need to know what error number 17 means. This article shows all available error numbers along with it descriptions. This article might be a handy reference for you, when you encounter an error number and you would
Errno.h In C
like to know what it means. In C programming language, there is an external variable called "errno". From this errno variable you can use some error handling functions to find out the error description and handle it appropriately. You have to include errno.h header file to use external variable errno. perror function prints error description in standard error. The strerror function returns a string describing the error code passed in the argument errnum. The following C code snippet tries to open a file how to use errno through open system call. There are two flags in the open call. O_CREAT flag is to create a file, if the file does not exist. O_EXCL flag is used with O_CREAT, if the file is already exist open call will fail with the proper error number. $ cat fileopen.c #include
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Strerror(errno)
- Structures C - Unions C - Bit Fields C - Typedef C - Input & errno python Output C - File I/O C - Preprocessors C - Header Files C - Type Casting C - Error Handling C - Recursion C - errno to string Variable Arguments C - Memory Management C - Command Line Arguments C Programming Resources C - Questions & Answers C - Quick Guide C - Useful Resources C - Discussion Selected Reading Developer's Best Practices Questions and Answers Effective Resume Writing http://www.thegeekstuff.com/2010/10/linux-error-codes/ HR Interview Questions Computer Glossary Who is Who C - Error Handling Advertisements Previous Page Next Page As such, C programming does not provide direct support for error handling but being a system programming language, it provides you access at lower level in the form of return values. Most of the C or even Unix function calls return -1 or NULL in case of any error and set an error code errno. It is set as a global variable and indicates https://www.tutorialspoint.com/cprogramming/c_error_handling.htm an error occurred during any function call. You can find various error codes defined in
Aug 2004 on RedHat 7.3 #define EPERM 1 /* Operation not permitted */ #define ENOENT 2 /* No such file or directory */ #define ESRCH 3 /* No such process */ #define EINTR 4 /* Interrupted system call */ #define EIO 5 /* I/O http://www-numi.fnal.gov/offline_software/srt_public_context/WebDocs/Errors/unix_system_errors.html error */ #define ENXIO 6 /* No such device or address */ #define E2BIG 7 /* http://en.cppreference.com/w/cpp/error/errno_macros Arg list too long */ #define ENOEXEC 8 /* Exec format error */ #define EBADF 9 /* Bad file number */ #define ECHILD 10 /* No child processes */ #define EAGAIN 11 /* Try again */ #define ENOMEM 12 /* Out of memory */ #define EACCES 13 /* Permission denied */ #define EFAULT 14 /* Bad address */ #define ENOTBLK 15 /* Block device required */ error number #define EBUSY 16 /* Device or resource busy */ #define EEXIST 17 /* File exists */ #define EXDEV 18 /* Cross-device link */ #define ENODEV 19 /* No such device */ #define ENOTDIR 20 /* Not a directory */ #define EISDIR 21 /* Is a directory */ #define EINVAL 22 /* Invalid argument */ #define ENFILE 23 /* File table overflow */ #define EMFILE 24 /* Too many open files */ #define ENOTTY 25 /* Not a typewriter */ #define ETXTBSY 26 c error number /* Text file busy */ #define EFBIG 27 /* File too large */ #define ENOSPC 28 /* No space left on device */ #define ESPIPE 29 /* Illegal seek */ #define EROFS 30 /* Read-only file system */ #define EMLINK 31 /* Too many links */ #define EPIPE 32 /* Broken pipe */ #define EDOM 33 /* Math argument out of domain of func */ #define ERANGE 34 /* Math result not representable */ #define EDEADLK 35 /* Resource deadlock would occur */ #define ENAMETOOLONG 36 /* File name too long */ #define ENOLCK 37 /* No record locks available */ #define ENOSYS 38 /* Function not implemented */ #define ENOTEMPTY 39 /* Directory not empty */ #define ELOOP 40 /* Too many symbolic links encountered */ #define EWOULDBLOCK EAGAIN /* Operation would block */ #define ENOMSG 42 /* No message of desired type */ #define EIDRM 43 /* Identifier removed */ #define ECHRNG 44 /* Channel number out of range */ #define EL2NSYNC 45 /* Level 2 not synchronized */ #define EL3HLT 46 /* Level 3 halted */ #define EL3RST 47 /* Level 3 reset */ #define ELNRNG 48 /* Link number out of range */ #define EUNATCH 49 /* Protocol driver not attached */ #define ENOCSI 50 /* No CSI structure available */ #define EL2HLT 51 /* Level 2 halted */ #define EBADE 52 /* Invalid exchange */ #define EBADR 53 /* Invalid request descriptor */ #define EXFULL 54 /* Exchange full
library Containers library Algorithms library Iterators library Numerics library Input/output library Localizations library Regular expressions library (C++11) Atomic operations library (C++11) Thread support library (C++11) Filesystem library (C++17) Technical Specifications [edit] Utilities library Type support (basic types, RTTI, type traits) Dynamic memory management Error handling Program utilities Variadic functions Date and time Function objects initializer_list(C++11) bitset hash(C++11) Relational operators rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>= optional, any and variant (C++17) optional any variant in_placein_place_tin_place_type_tin_place_index_t Pairs and tuples pair tuple(C++11) apply(C++17) make_from_tuple(C++17) piecewise_construct_t(C++11) piecewise_construct(C++11) integer_sequence(C++14) Swap, forward and move swap exchange(C++14) forward(C++11) move(C++11) move_if_noexcept(C++11) Type operations declval(C++11) as_const(C++17) [edit] Error handling Exception handling exception uncaught_exceptionuncaught_exceptions(C++17) exception_ptr(C++11) make_exception_ptr(C++11) current_exception(C++11) rethrow_exception(C++11) nested_exception(C++11) throw_with_nested(C++11) rethrow_if_nested(C++11) Exception handling failures terminate terminate_handler get_terminate(C++11) set_terminate unexpected(deprecated) bad_exception unexpected_handler(deprecated) get_unexpected(C++11)(deprecated) set_unexpected(deprecated) Exception categories logic_error invalid_argument domain_error length_error out_of_range runtime_error range_error overflow_error underflow_error tx_exception(TM TS) Error codes Error codes errno Assertions assert system_error facility error_category(C++11) generic_category(C++11) system_category(C++11) error_condition(C++11) errc(C++11) error_code(C++11) system_error(C++11) [edit] Each of the macros defined in