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