Tcl_SetErrno(3tcl) Tcl Library Procedures Tcl_SetErrno(3tcl)
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NAME
Tcl_SetErrno, Tcl_GetErrno, Tcl_ErrnoId, Tcl_ErrnoMsg - manipulate er-
rno 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 bound-
aries on some platforms.
Tcl_SetErrno sets the errno variable to the value of the errorCode ar-
gument 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 di-
rectly.
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_Er-
rnoMsg returns a human-readable string such as “permission denied” that
corresponds to the value of its errorCode argument. The errorCode ar-
gument 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(3tcl)
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