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Member "SAOImageDS9/tcl8.6/doc/SetErrno.3" (13 Nov 2019, 2092 Bytes) of package /linux/misc/ds9.8.1.tar.gz:


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Tcl_SetErrno

NAME
SYNOPSIS
ARGUMENTS
DESCRIPTION
KEYWORDS

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

A POSIX error code such as ENOENT.

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 that corresponds to the current value of errno. Tcl_ErrnoMsg returns a human-readable string such as 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