Tcl_SetErrno(3)             Tcl Library Procedures             Tcl_SetErrno(3)

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NAME
       Tcl_SetErrno, Tcl_GetErrno, Tcl_ErrnoId, Tcl_ErrnoMsg - manipulate
       errno to store and retrieve error codes

SYNOPSIS
       #include <tcl.h>

       void
       Tcl_SetErrno(errorCode)

       int
       Tcl_GetErrno()

       const char *
       Tcl_ErrnoId()

       const char *
       Tcl_ErrnoMsg(errorCode)


ARGUMENTS
       int errorCode (in)          A POSIX error code such as ENOENT.
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DESCRIPTION
       Tcl_SetErrno and Tcl_GetErrno provide portable access to the errno
       variable, which is used to record a POSIX error code after system calls
       and other operations such as Tcl_Gets.  These procedures are necessary
       because global variable accesses cannot be made across module
       boundaries on some platforms.

       Tcl_SetErrno sets the errno variable to the value of the errorCode
       argument C procedures that wish to return error information to their
       callers via errno should call Tcl_SetErrno rather than setting errno
       directly.

       Tcl_GetErrno returns the current value of errno.  Procedures wishing to
       access errno should call this procedure instead of accessing errno
       directly.

       Tcl_ErrnoId and Tcl_ErrnoMsg return string representations of errno
       values.  Tcl_ErrnoId returns a machine-readable textual identifier such
       as "EACCES" that corresponds to the current value of errno.
       Tcl_ErrnoMsg returns a human-readable string such as "permission
       denied" that corresponds to the value of its errorCode argument.  The
       errorCode argument is typically the value returned by Tcl_GetErrno.
       The strings returned by these functions are statically allocated and
       the caller must not free or modify them.


KEYWORDS
       errno, error code, global variables

Tcl                                   8.3                      Tcl_SetErrno(3)