Tcl_GetOpenFile(3)

Tcl_GetOpenFile(3)   Tcl Library Procedures    Tcl_GetOpenFile(3)

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NAME

     Tcl_GetOpenFile - Return a FILE* for a channel registered in
     the given interpreter (Unix only)

SYNOPSIS

     #include <tcl.h>

     int
     Tcl_GetOpenFile(interp, chanID, write, checkUsage, filePtr)

ARGUMENTS

     Tcl_Interp *interp (in)             Tcl   interpreter   from
                                         which  file handle is to
                                         be obtained.

     const char *chanID (in)             String identifying chan-
                                         nel,  such  as  stdin or
                                         file4.

     int write (in)                      Non-zero means the  file
                                         will  be  used for writ-
                                         ing, zero means it  will
                                         be used for reading.

     int checkUsage (in)                 If  non-zero,  then   an
                                         error  will be generated
                                         if  the  file  was   not
                                         opened  for  the  access
                                         indicated by write.

     ClientData *filePtr (out)           Points to word in  which
                                         to store pointer to FILE
                                         structure for  the  file
                                         given by chanID.
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DESCRIPTION

     Tcl_GetOpenFile takes as argument a file identifier  of  the
     form  returned by the open command and returns at *filePtr a
     pointer to the FILE structure for the file.  The write argu-
     ment  indicates  whether  the  FILE pointer will be used for
     reading or writing.  In some cases, such as a  channel  that
     connects  to  a  pipeline  of  subprocesses,  different FILE
     pointers  will  be  returned  for   reading   and   writing.
     Tcl_GetOpenFile normally returns TCL_OK.  If an error occurs
     in Tcl_GetOpenFile (e.g. chanID did not make  any  sense  or
     checkUsage  was  set  and  the  file  was not opened for the
     access specified by write) then TCL_ERROR  is  returned  and

Tcl                     Last change: 8.0                        1

Tcl_GetOpenFile(3)   Tcl Library Procedures    Tcl_GetOpenFile(3)

     the  interpreter's result will contain an error message.  In
     the current implementation checkUsage is  ignored  and  con-
     sistency checks are always performed.

     Note that this interface is only supported on the Unix plat-
     form.

KEYWORDS

     channel, file handle, permissions, pipeline, read, write

Tcl                     Last change: 8.0                        2