Tcl_SetErrno(3)

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 argu-
     ment is typically the value returned by  Tcl_GetErrno.   The

Tcl                     Last change: 8.3                        1

Tcl_SetErrno(3)      Tcl Library Procedures       Tcl_SetErrno(3)

     strings returned by these functions are statically allocated
     and the caller must not free or modify them.

KEYWORDS

     errno, error code, global variables

Tcl                     Last change: 8.3                        2