Standard library header <errno.h>

This header is part of the error handling library.

Error numbers

errno	macro which expands to POSIX-compatible thread-local error number variable (macro variable)
E2BIG, EACCES, ..., EXDEV	macros for standard POSIX-compatible error conditions (macro constant)

Synopsis

#define EDOM   /* implementation-defined */
#define EILSEQ /* implementation-defined */
#define ERANGE /* implementation-defined */

#define errno  /* implementation-defined */

// Only if the implementation defines __STDC_LIB_EXT1__ and additionally the user code
// defines __STDC_WANT_LIB_EXT1__ before any inclusion of <errno.h>:
#ifdef __STDC_WANT_LIB_EXT1__
#define __STDC_LIB_EXT1__  /* implementation-defined */
#define errno_t            /* implementation-defined */
#endif