1Tcl_SetErrno(3)             Tcl Library Procedures             Tcl_SetErrno(3)
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NAME

8       Tcl_SetErrno,  Tcl_GetErrno, Tcl_ErrnoId, Tcl_ErrnoMsg - manipulate er‐
9       rno to store and retrieve error codes
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SYNOPSIS

12       #include <tcl.h>
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14       void
15       Tcl_SetErrno(errorCode)
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17       int
18       Tcl_GetErrno()
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20       const char *
21       Tcl_ErrnoId()
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23       const char *
24       Tcl_ErrnoMsg(errorCode)
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ARGUMENTS

28       int errorCode (in)          A POSIX error code such as ENOENT.
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DESCRIPTION

33       Tcl_SetErrno and Tcl_GetErrno provide  portable  access  to  the  errno
34       variable, which is used to record a POSIX error code after system calls
35       and other operations such as Tcl_Gets.  These procedures are  necessary
36       because  global  variable  accesses cannot be made across module bound‐
37       aries on some platforms.
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39       Tcl_SetErrno sets the errno variable to the value of the errorCode  ar‐
40       gument  C  procedures  that  wish  to return error information to their
41       callers via errno should call Tcl_SetErrno rather  than  setting  errno
42       directly.
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44       Tcl_GetErrno returns the current value of errno.  Procedures wishing to
45       access errno should call this procedure instead of accessing errno  di‐
46       rectly.
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48       Tcl_ErrnoId  and  Tcl_ErrnoMsg  return  string representations of errno
49       values.  Tcl_ErrnoId returns a machine-readable textual identifier such
50       as  “EACCES”  that  corresponds to the current value of errno.  Tcl_Er‐
51       rnoMsg returns a human-readable string such as “permission denied” that
52       corresponds  to the value of its errorCode argument.  The errorCode ar‐
53       gument is typically the value returned by  Tcl_GetErrno.   The  strings
54       returned  by  these  functions  are statically allocated and the caller
55       must not free or modify them.
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KEYWORDS

59       errno, error code, global variables
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63Tcl                                   8.3                      Tcl_SetErrno(3)
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