SYNOPSIS
#include <errno.h>
extern int errno;
DESCRIPTION
The errno variable is used by many functions to return error values. The value of errno is defined only after a call to a function for which it is explicitly stated to be set and until it is changed by the next function call. The value of errno should only be examined when it is indicated to be valid by a function's return value. Programs should obtain the definition of errno by the inclusion of <errno.h>. The practice of defining errno in a program as
extern int errno;
(without including <errno.h>) is unsupported.
It is unspecified whether errno is a macro or an identifier declared with external linkage. If a macro definition is suppressed in order to access the actual object, or a program defines an identifier with the name errno, the behavior is undefined.
The symbolic values stored in errno are documented in the RETURN VALUES section on all relevant pages.
CONFORMANCE
UNIX 98, with exceptions.
PORTING ISSUES
Not all Win32 error codes can be represented as UNIX errno values.
In these cases, errno is set to the negative of the Win32
error number. The
AVAILABILITY
PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Professional Developers 64-Bit Edition
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition
SEE ALSO
- Functions:
perror() ,strerror()
- Miscellaneous:
- h_errno, sys_errlist, sys_nerr
PTC MKS Toolkit 10.4 Documentation Build 39.